| Age | Commit message (Collapse) | Author | Files | Lines |
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Map the leaf SPTE when handling a TDP MMU page fault if and only if the
target level is reached. A recent commit reworked the retry logic and
incorrectly assumed that walking SPTEs would never "fail", as the loop
either bails (retries) or installs parent SPs. However, the iterator
itself will bail early if it detects a frozen (REMOVED) SPTE when
stepping down. The TDP iterator also rereads the current SPTE before
stepping down specifically to avoid walking into a part of the tree that
is being removed, which means it's possible to terminate the loop without
the guts of the loop observing the frozen SPTE, e.g. if a different task
zaps a parent SPTE between the initial read and try_step_down()'s refresh.
Mapping a leaf SPTE at the wrong level results in all kinds of badness as
page table walkers interpret the SPTE as a page table, not a leaf, and
walk into the weeds.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 1025 at arch/x86/kvm/mmu/tdp_mmu.c:1070 kvm_tdp_mmu_map+0x481/0x510
Modules linked in: kvm_intel
CPU: 1 PID: 1025 Comm: nx_huge_pages_t Tainted: G W 6.1.0-rc4+ #64
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_tdp_mmu_map+0x481/0x510
RSP: 0018:ffffc9000072fba8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffffc9000072fcc0 RCX: 0000000000000027
RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff888277c5b4c8
RBP: ffff888107d45a10 R08: ffff888277c5b4c0 R09: ffffc9000072fa48
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc9000073a0e0
R13: ffff88810fc54800 R14: ffff888107d1ae60 R15: ffff88810fc54f90
FS: 00007fba9f853740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010aa7a003 CR4: 0000000000172ea0
Call Trace:
<TASK>
kvm_tdp_page_fault+0x10c/0x130
kvm_mmu_page_fault+0x103/0x680
vmx_handle_exit+0x132/0x5a0 [kvm_intel]
vcpu_enter_guest+0x60c/0x16f0
kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
kvm_vcpu_ioctl+0x271/0x660
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x2b/0x50
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
---[ end trace 0000000000000000 ]---
Invalid SPTE change: cannot replace a present leaf
SPTE with another present leaf SPTE mapping a
different PFN!
as_id: 0 gfn: 100200 old_spte: 600000112400bf3 new_spte: 6000001126009f3 level: 2
------------[ cut here ]------------
kernel BUG at arch/x86/kvm/mmu/tdp_mmu.c:559!
invalid opcode: 0000 [#1] SMP
CPU: 1 PID: 1025 Comm: nx_huge_pages_t Tainted: G W 6.1.0-rc4+ #64
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:__handle_changed_spte.cold+0x95/0x9c
RSP: 0018:ffffc9000072faf8 EFLAGS: 00010246
RAX: 00000000000000c1 RBX: ffffc90000731000 RCX: 0000000000000027
RDX: 0000000000000000 RSI: 00000000ffffdfff RDI: ffff888277c5b4c8
RBP: 0600000112400bf3 R08: ffff888277c5b4c0 R09: ffffc9000072f9a0
R10: 0000000000000001 R11: 0000000000000001 R12: 06000001126009f3
R13: 0000000000000002 R14: 0000000012600901 R15: 0000000012400b01
FS: 00007fba9f853740(0000) GS:ffff888277c40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010aa7a003 CR4: 0000000000172ea0
Call Trace:
<TASK>
kvm_tdp_mmu_map+0x3b0/0x510
kvm_tdp_page_fault+0x10c/0x130
kvm_mmu_page_fault+0x103/0x680
vmx_handle_exit+0x132/0x5a0 [kvm_intel]
vcpu_enter_guest+0x60c/0x16f0
kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
kvm_vcpu_ioctl+0x271/0x660
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x2b/0x50
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
Modules linked in: kvm_intel
---[ end trace 0000000000000000 ]---
Fixes: 63d28a25e04c ("KVM: x86/mmu: simplify kvm_tdp_mmu_map flow when guest has to retry")
Cc: Robert Hoo <robert.hu@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213033030.83345-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Hoist the is_removed_spte() check above the "level == goal_level" check
when walking SPTEs during a TDP MMU page fault to avoid attempting to map
a leaf entry if said entry is frozen by a different task/vCPU.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 939 at arch/x86/kvm/mmu/tdp_mmu.c:653 kvm_tdp_mmu_map+0x269/0x4b0
Modules linked in: kvm_intel
CPU: 3 PID: 939 Comm: nx_huge_pages_t Not tainted 6.1.0-rc4+ #67
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:kvm_tdp_mmu_map+0x269/0x4b0
RSP: 0018:ffffc9000068fba8 EFLAGS: 00010246
RAX: 00000000000005a0 RBX: ffffc9000068fcc0 RCX: 0000000000000005
RDX: ffff88810741f000 RSI: ffff888107f04600 RDI: ffffc900006a3000
RBP: 060000010b000bf3 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 000ffffffffff000 R12: 0000000000000005
R13: ffff888113670000 R14: ffff888107464958 R15: 0000000000000000
FS: 00007f01c942c740(0000) GS:ffff888277cc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000117013006 CR4: 0000000000172ea0
Call Trace:
<TASK>
kvm_tdp_page_fault+0x10c/0x130
kvm_mmu_page_fault+0x103/0x680
vmx_handle_exit+0x132/0x5a0 [kvm_intel]
vcpu_enter_guest+0x60c/0x16f0
kvm_arch_vcpu_ioctl_run+0x1e2/0x9d0
kvm_vcpu_ioctl+0x271/0x660
__x64_sys_ioctl+0x80/0xb0
do_syscall_64+0x2b/0x50
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
---[ end trace 0000000000000000 ]---
Fixes: 63d28a25e04c ("KVM: x86/mmu: simplify kvm_tdp_mmu_map flow when guest has to retry")
Cc: Robert Hoo <robert.hu@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Robert Hoo <robert.hu@linux.intel.com>
Message-Id: <20221213033030.83345-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When stuffing the allowed secondary execution controls for nested VMX in
response to CPUID updates, don't set the allowed-1 bit for a feature that
isn't supported by KVM, i.e. isn't allowed by the canonical vmcs_config.
WARN if KVM attempts to manipulate a feature that isn't supported. All
features that are currently stuffed are always advertised to L1 for
nested VMX if they are supported in KVM's base configuration, and no
additional features should ever be added to the CPUID-induced stuffing
(updating VMX MSRs in response to CPUID updates is a long-standing KVM
flaw that is slowly being fixed).
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213062306.667649-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Set ENABLE_USR_WAIT_PAUSE in KVM's supported VMX MSR configuration if the
feature is supported in hardware and enabled in KVM's base, non-nested
configuration, i.e. expose ENABLE_USR_WAIT_PAUSE to L1 if it's supported.
This fixes a bug where saving/restoring, i.e. migrating, a vCPU will fail
if WAITPKG (the associated CPUID feature) is enabled for the vCPU, and
obviously allows L1 to enable the feature for L2.
KVM already effectively exposes ENABLE_USR_WAIT_PAUSE to L1 by stuffing
the allowed-1 control ina vCPU's virtual MSR_IA32_VMX_PROCBASED_CTLS2 when
updating secondary controls in response to KVM_SET_CPUID(2), but (a) that
depends on flawed code (KVM shouldn't touch VMX MSRs in response to CPUID
updates) and (b) runs afoul of vmx_restore_control_msr()'s restriction
that the guest value must be a strict subset of the supported host value.
Although no past commit explicitly enabled nested support for WAITPKG,
doing so is safe and functionally correct from an architectural
perspective as no additional KVM support is needed to virtualize TPAUSE,
UMONITOR, and UMWAIT for L2 relative to L1, and KVM already forwards
VM-Exits to L1 as necessary (commit bf653b78f960, "KVM: vmx: Introduce
handle_unexpected_vmexit and handle WAITPKG vmexit").
Note, KVM always keeps the hosts MSR_IA32_UMWAIT_CONTROL resident in
hardware, i.e. always runs both L1 and L2 with the host's power management
settings for TPAUSE and UMWAIT. See commit bf09fb6cba4f ("KVM: VMX: Stop
context switching MSR_IA32_UMWAIT_CONTROL") for more details.
Fixes: e69e72faa3a0 ("KVM: x86: Add support for user wait instructions")
Cc: stable@vger.kernel.org
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reported-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20221213062306.667649-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Explicitly drop the result of kvm_vcpu_write_guest() when writing the
"launch state" as part of VMCLEAR emulation, and add a comment to call
out that KVM's behavior is architecturally valid. Intel's pseudocode
effectively says that VMCLEAR is a nop if the target VMCS address isn't
in memory, e.g. if the address points at MMIO.
Add a FIXME to call out that suppressing failures on __copy_to_user() is
wrong, as memory (a memslot) does exist in that case. Punt the issue to
the future as open coding kvm_vcpu_write_guest() just to make sure the
guest dies with -EFAULT isn't worth the extra complexity. The flaw will
need to be addressed if KVM ever does something intelligent on uaccess
failures, e.g. to support post-copy demand paging, but in that case KVM
will need a more thorough overhaul, i.e. VMCLEAR shouldn't need to open
code a core KVM helper.
No functional change intended.
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527765 ("Error handling issues")
Fixes: 587d7e72aedc ("kvm: nVMX: VMCLEAR should not cause the vCPU to shut down")
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221220154224.526568-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Zero out the valid_bank_mask when using the fast variant of
HVCALL_SEND_IPI_EX to send IPIs to all vCPUs. KVM requires the "var_cnt"
and "valid_bank_mask" inputs to be consistent even when targeting all
vCPUs. See commit bd1ba5732bb9 ("KVM: x86: Get the number of Hyper-V
sparse banks from the VARHEAD field").
Fixes: 998489245d84 ("KVM: selftests: Hyper-V PV IPI selftest")
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221219220416.395329-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a sanity check in kvm_handle_memory_failure() to assert that a valid
x86_exception structure is provided if the memory "failure" wants to
propagate a fault into the guest. If a memory failure happens during a
direct guest physical memory access, e.g. for nested VMX, KVM hardcodes
the failure to X86EMUL_IO_NEEDED and doesn't provide an exception pointer
(because the exception struct would just be filled with garbage).
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221220153427.514032-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_apic_hw_enabled() only needs to return bool, there is no place
to use the return value of MSR_IA32_APICBASE_ENABLE.
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Message-Id: <CAPm50aJ=BLXNWT11+j36Dd6d7nz2JmOBk4u7o_NPQ0N61ODu1g@mail.gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In kvm_hv_flush_tlb(), 'data_offset' and 'consumed_xmm_halves' variables
are used in a mutually exclusive way: in 'hc->fast' we count in 'XMM
halves' and increase 'data_offset' otherwise. Coverity discovered, that in
one case both variables are incremented unconditionally. This doesn't seem
to cause any issues as the only user of 'data_offset'/'consumed_xmm_halves'
data is kvm_hv_get_tlb_flush_entries() -> kvm_hv_get_hc_data() which also
takes into account 'hc->fast' but is still worth fixing.
To make things explicit, put 'data_offset' and 'consumed_xmm_halves' to
'struct kvm_hv_hcall' as a union and use at call sites. This allows to
remove explicit 'data_offset'/'consumed_xmm_halves' parameters from
kvm_hv_get_hc_data()/kvm_get_sparse_vp_set()/kvm_hv_get_tlb_flush_entries()
helpers.
Note: 'struct kvm_hv_hcall' is allocated on stack in kvm_hv_hypercall() and
is not zeroed, consumers are supposed to initialize the appropriate field
if needed.
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527764 ("Uninitialized variables")
Fixes: 260970862c88 ("KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221208102700.959630-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When scanning userspace I/OAPIC entries, intercept EOI for level-triggered
IRQs if the current vCPU has a pending and/or in-service IRQ for the
vector in its local API, even if the vCPU doesn't match the new entry's
destination. This fixes a race between userspace I/OAPIC reconfiguration
and IRQ delivery that results in the vector's bit being left set in the
remote IRR due to the eventual EOI not being forwarded to the userspace
I/OAPIC.
Commit 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC
reconfigure race") fixed the in-kernel IOAPIC, but not the userspace
IOAPIC configuration, which has a similar race.
Fixes: 0fc5a36dd6b3 ("KVM: x86: ioapic: Fix level-triggered EOI and IOAPIC reconfigure race")
Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221208094415.12723-1-attofari@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The current vPMU can reuse the same pmc->perf_event for the same
hardware event via pmc_pause/resume_counter(), but this optimization
does not apply to a portion of the TSX events (e.g., "event=0x3c,in_tx=1,
in_tx_cp=1"), where event->attr.sample_period is legally zero at creation,
thus making the perf call to perf_event_period() meaningless (no need to
adjust sample period in this case), and instead causing such reusable
perf_events to be repeatedly released and created.
Avoid releasing zero sample_period events by checking is_sampling_event()
to follow the previously enable/disable optimization.
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20221207071506.15733-2-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add ReST formatting to the set of userspace MSR exits/flags so that the
resulting HTML docs generate a table instead of malformed gunk. This
also fixes a warning that was introduced by a recent cleanup of the
relevant documentation (yay copy+paste).
>> Documentation/virt/kvm/api.rst:7287: WARNING: Block quote ends
without a blank line; unexpected unindent.
Fixes: 1ae099540e8c ("KVM: x86: Allow deflecting unknown MSR accesses to user space")
Fixes: 1f158147181b ("KVM: x86: Clean up KVM_CAP_X86_USER_SPACE_MSR documentation")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221207000959.2035098-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86 Xen-for-KVM:
* Allow the Xen runstate information to cross a page boundary
* Allow XEN_RUNSTATE_UPDATE flag behaviour to be configured
* add support for 32-bit guests in SCHEDOP_poll
x86 fixes:
* One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).
* Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few
years back when eliminating unnecessary barriers when switching between
vmcs01 and vmcs02.
* Clean up the MSR filter docs.
* Clean up vmread_error_trampoline() to make it more obvious that params
must be passed on the stack, even for x86-64.
* Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective
of the current guest CPUID.
* Fudge around a race with TSC refinement that results in KVM incorrectly
thinking a guest needs TSC scaling when running on a CPU with a
constant TSC, but no hardware-enumerated TSC frequency.
* Advertise (on AMD) that the SMM_CTL MSR is not supported
* Remove unnecessary exports
Selftests:
* Fix an inverted check in the access tracking perf test, and restore
support for asserting that there aren't too many idle pages when
running on bare metal.
* Fix an ordering issue in the AMX test introduced by recent conversions
to use kvm_cpu_has(), and harden the code to guard against similar bugs
in the future. Anything that tiggers caching of KVM's supported CPUID,
kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if
the caching occurs before the test opts in via prctl().
* Fix build errors that occur in certain setups (unsure exactly what is
unique about the problematic setup) due to glibc overriding
static_assert() to a variant that requires a custom message.
* Introduce actual atomics for clear/set_bit() in selftests
Documentation:
* Remove deleted ioctls from documentation
* Various fixes
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MEM_REGION_TEST_DATA is meant to hold data explicitly used by a
selftest, not implicit allocations due to the selftests infrastructure.
Allocate the ucall pool from MEM_REGION_DATA much like the rest of the
selftests library allocations.
Fixes: 426729b2cf2e ("KVM: selftests: Add ucall pool based implementation")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20221207214809.489070-5-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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An interesting feature of the Arm architecture is that the stage-1 MMU
supports two distinct VA regions, controlled by TTBR{0,1}_EL1. As KVM
selftests on arm64 only uses TTBR0_EL1, the VA space is constrained to
[0, 2^(va_bits-1)). This is different from other architectures that
allow for addressing low and high regions of the VA space from a single
page table.
KVM selftests' VA space allocator presumes the valid address range is
split between low and high memory based the MSB, which of course is a
poor match for arm64's TTBR0 region.
Allow architectures to override the default VA space layout. Make use of
the override to align vpages_valid with the behavior of TTBR0 on arm64.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20221207214809.489070-4-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for 6.2
- Enable the per-vcpu dirty-ring tracking mechanism, together with an
option to keep the good old dirty log around for pages that are
dirtied by something other than a vcpu.
- Switch to the relaxed parallel fault handling, using RCU to delay
page table reclaim and giving better performance under load.
- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
option, which multi-process VMMs such as crosvm rely on.
- Merge the pKVM shadow vcpu state tracking that allows the hypervisor
to have its own view of a vcpu, keeping that state private.
- Add support for the PMUv3p5 architecture revision, bringing support
for 64bit counters on systems that support it, and fix the
no-quite-compliant CHAIN-ed counter support for the machines that
actually exist out there.
- Fix a handful of minor issues around 52bit VA/PA support (64kB pages
only) as a prefix of the oncoming support for 4kB and 16kB pages.
- Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
stage-2 faults and access tracking. You name it, we got it, we
probably broke it.
- Pick a small set of documentation and spelling fixes, because no
good merge window would be complete without those.
As a side effect, this tag also drags:
- The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
series
- A shared branch with the arm64 tree that repaints all the system
registers to match the ARM ARM's naming, and resulting in
interesting conflicts
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Merge arm64's sysreg repainting branch to avoid too many
ugly conflicts...
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/misc-6.2:
: .
: Misc fixes for 6.2:
:
: - Fix formatting for the pvtime documentation
:
: - Fix a comment in the VHE-specific Makefile
: .
KVM: arm64: Fix typo in comment
KVM: arm64: Fix pvtime documentation
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/pmu-unchained:
: .
: PMUv3 fixes and improvements:
:
: - Make the CHAIN event handling strictly follow the architecture
:
: - Add support for PMUv3p5 (64bit counters all the way)
:
: - Various fixes and cleanups
: .
KVM: arm64: PMU: Fix period computation for 64bit counters with 32bit overflow
KVM: arm64: PMU: Sanitise PMCR_EL0.LP on first vcpu run
KVM: arm64: PMU: Simplify PMCR_EL0 reset handling
KVM: arm64: PMU: Replace version number '0' with ID_AA64DFR0_EL1_PMUVer_NI
KVM: arm64: PMU: Make kvm_pmc the main data structure
KVM: arm64: PMU: Simplify vcpu computation on perf overflow notification
KVM: arm64: PMU: Allow PMUv3p5 to be exposed to the guest
KVM: arm64: PMU: Implement PMUv3p5 long counter support
KVM: arm64: PMU: Allow ID_DFR0_EL1.PerfMon to be set from userspace
KVM: arm64: PMU: Allow ID_AA64DFR0_EL1.PMUver to be set from userspace
KVM: arm64: PMU: Move the ID_AA64DFR0_EL1.PMUver limit to VM creation
KVM: arm64: PMU: Do not let AArch32 change the counters' top 32 bits
KVM: arm64: PMU: Simplify setting a counter to a specific value
KVM: arm64: PMU: Add counter_index_to_*reg() helpers
KVM: arm64: PMU: Only narrow counters that are not 64bit wide
KVM: arm64: PMU: Narrow the overflow checking when required
KVM: arm64: PMU: Distinguish between 64bit counter and 64bit overflow
KVM: arm64: PMU: Always advertise the CHAIN event
KVM: arm64: PMU: Align chained counter implementation with architecture pseudocode
arm64: Add ID_DFR0_EL1.PerfMon values for PMUv3p7 and IMP_DEF
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/mte-map-shared:
: .
: Update the MTE support to allow the VMM to use shared mappings
: to back the memslots exposed to MTE-enabled guests.
:
: Patches courtesy of Catalin Marinas and Peter Collingbourne.
: .
: Fix a number of issues with MTE, such as races on the tags
: being initialised vs the PG_mte_tagged flag as well as the
: lack of support for VM_SHARED when KVM is involved.
:
: Patches from Catalin Marinas and Peter Collingbourne.
: .
Documentation: document the ABI changes for KVM_CAP_ARM_MTE
KVM: arm64: permit all VM_MTE_ALLOWED mappings with MTE enabled
KVM: arm64: unify the tests for VMAs in memslots when MTE is enabled
arm64: mte: Lock a page for MTE tag initialisation
mm: Add PG_arch_3 page flag
KVM: arm64: Simplify the sanitise_mte_tags() logic
arm64: mte: Fix/clarify the PG_mte_tagged semantics
mm: Do not enable PG_arch_2 for all 64-bit architectures
Signed-off-by: Marc Zyngier <maz@kernel.org>
|
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* kvm-arm64/pkvm-vcpu-state: (25 commits)
: .
: Large drop of pKVM patches from Will Deacon and co, adding
: a private vm/vcpu state at EL2, managed independently from
: the EL1 state. From the cover letter:
:
: "This is version six of the pKVM EL2 state series, extending the pKVM
: hypervisor code so that it can dynamically instantiate and manage VM
: data structures without the host being able to access them directly.
: These structures consist of a hyp VM, a set of hyp vCPUs and the stage-2
: page-table for the MMU. The pages used to hold the hypervisor structures
: are returned to the host when the VM is destroyed."
: .
KVM: arm64: Use the pKVM hyp vCPU structure in handle___kvm_vcpu_run()
KVM: arm64: Don't unnecessarily map host kernel sections at EL2
KVM: arm64: Explicitly map 'kvm_vgic_global_state' at EL2
KVM: arm64: Maintain a copy of 'kvm_arm_vmid_bits' at EL2
KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the host
KVM: arm64: Return guest memory from EL2 via dedicated teardown memcache
KVM: arm64: Instantiate guest stage-2 page-tables at EL2
KVM: arm64: Consolidate stage-2 initialisation into a single function
KVM: arm64: Add generic hyp_memcache helpers
KVM: arm64: Provide I-cache invalidation by virtual address at EL2
KVM: arm64: Initialise hypervisor copies of host symbols unconditionally
KVM: arm64: Add per-cpu fixmap infrastructure at EL2
KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1
KVM: arm64: Add infrastructure to create and track pKVM instances at EL2
KVM: arm64: Rename 'host_kvm' to 'host_mmu'
KVM: arm64: Add hyp_spinlock_t static initializer
KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.h
KVM: arm64: Add helpers to pin memory shared with the hypervisor at EL2
KVM: arm64: Prevent the donation of no-map pages
KVM: arm64: Implement do_donate() helper for donating memory
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/parallel-faults:
: .
: Parallel stage-2 fault handling, courtesy of Oliver Upton.
: From the cover letter:
:
: "Presently KVM only takes a read lock for stage 2 faults if it believes
: the fault can be fixed by relaxing permissions on a PTE (write unprotect
: for dirty logging). Otherwise, stage 2 faults grab the write lock, which
: predictably can pile up all the vCPUs in a sufficiently large VM.
:
: Like the TDP MMU for x86, this series loosens the locking around
: manipulations of the stage 2 page tables to allow parallel faults. RCU
: and atomics are exploited to safely build/destroy the stage 2 page
: tables in light of multiple software observers."
: .
KVM: arm64: Reject shared table walks in the hyp code
KVM: arm64: Don't acquire RCU read lock for exclusive table walks
KVM: arm64: Take a pointer to walker data in kvm_dereference_pteref()
KVM: arm64: Handle stage-2 faults in parallel
KVM: arm64: Make table->block changes parallel-aware
KVM: arm64: Make leaf->leaf PTE changes parallel-aware
KVM: arm64: Make block->table PTE changes parallel-aware
KVM: arm64: Split init and set for table PTE
KVM: arm64: Atomically update stage 2 leaf attributes in parallel walks
KVM: arm64: Protect stage-2 traversal with RCU
KVM: arm64: Tear down unlinked stage-2 subtree after break-before-make
KVM: arm64: Use an opaque type for pteps
KVM: arm64: Add a helper to tear down unlinked stage-2 subtrees
KVM: arm64: Don't pass kvm_pgtable through kvm_pgtable_walk_data
KVM: arm64: Pass mm_ops through the visitor context
KVM: arm64: Stash observed pte value in visitor context
KVM: arm64: Combine visitor arguments into a context structure
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/dirty-ring:
: .
: Add support for the "per-vcpu dirty-ring tracking with a bitmap
: and sprinkles on top", courtesy of Gavin Shan.
:
: This branch drags the kvmarm-fixes-6.1-3 tag which was already
: merged in 6.1-rc4 so that the branch is in a working state.
: .
KVM: Push dirty information unconditionally to backup bitmap
KVM: selftests: Automate choosing dirty ring size in dirty_log_test
KVM: selftests: Clear dirty ring states between two modes in dirty_log_test
KVM: selftests: Use host page size to map ring buffer in dirty_log_test
KVM: arm64: Enable ring-based dirty memory tracking
KVM: Support dirty ring in conjunction with bitmap
KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h
KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/52bit-fixes:
: .
: 52bit PA fixes, courtesy of Ryan Roberts. From the cover letter:
:
: "I've been adding support for FEAT_LPA2 to KVM and as part of that work have been
: testing various (84) configurations of HW, host and guest kernels on FVP. This
: has thrown up a couple of pre-existing bugs, for which the fixes are provided."
: .
KVM: arm64: Fix benign bug with incorrect use of VA_BITS
KVM: arm64: Fix PAR_TO_HPFAR() to work independently of PA_BITS.
KVM: arm64: Fix kvm init failure when mode!=vhe and VA_BITS=52.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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get_user_mapping_size() uses kvm's pgtable library to walk a user space
page table created by the kernel, and in doing so, passes metadata
that the library needs, including ia_bits, which defines the size of the
input address.
For the case where the kernel is compiled for 52 VA bits but runs on HW
that does not support LVA, it will fall back to 48 VA bits at runtime.
Therefore we must use vabits_actual rather than VA_BITS to get the true
address size.
This is benign in the current code base because the pgtable library only
uses it for error checking.
Fixes: 6011cf68c885 ("KVM: arm64: Walk userspace page tables to compute the THP mapping size")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221205114031.3972780-1-ryan.roberts@arm.com
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* kvm-arm64/selftest/access-tracking:
: .
: Small series to add support for arm64 to access_tracking_perf_test and
: correct a couple bugs along the way.
:
: Patches courtesy of Oliver Upton.
: .
KVM: selftests: Build access_tracking_perf_test for arm64
KVM: selftests: Have perf_test_util signal when to stop vCPUs
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/selftest/s2-faults:
: .
: New KVM/arm64 selftests exercising various sorts of S2 faults, courtesy
: of Ricardo Koller. From the cover letter:
:
: "This series adds a new aarch64 selftest for testing stage 2 fault handling
: for various combinations of guest accesses (e.g., write, S1PTW), backing
: sources (e.g., anon), and types of faults (e.g., read on hugetlbfs with a
: hole, write on a readonly memslot). Each test tries a different combination
: and then checks that the access results in the right behavior (e.g., uffd
: faults with the right address and write/read flag). [...]"
: .
KVM: selftests: aarch64: Add mix of tests into page_fault_test
KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test
KVM: selftests: aarch64: Add dirty logging tests into page_fault_test
KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test
KVM: selftests: aarch64: Add aarch64/page_fault_test
KVM: selftests: Use the right memslot for code, page-tables, and data allocations
KVM: selftests: Fix alignment in virt_arch_pgd_alloc() and vm_vaddr_alloc()
KVM: selftests: Add vm->memslots[] and enum kvm_mem_region_type
KVM: selftests: Stash backing_src_type in struct userspace_mem_region
tools: Copy bitfield.h from the kernel sources
KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h macros
KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()
KVM: selftests: aarch64: Add virt_get_pte_hva() library function
KVM: selftests: Add a userfaultfd library
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/selftest/linked-bps:
: .
: Additional selftests for the arm64 breakpoints/watchpoints,
: courtesy of Reiji Watanabe. From the cover letter:
:
: "This series adds test cases for linked {break,watch}points to the
: debug-exceptions test, and expands {break,watch}point tests to
: use non-zero {break,watch}points (the current test always uses
: {break,watch}point#0)."
: .
KVM: arm64: selftests: Test with every breakpoint/watchpoint
KVM: arm64: selftests: Add a test case for a linked watchpoint
KVM: arm64: selftests: Add a test case for a linked breakpoint
KVM: arm64: selftests: Change debug_version() to take ID_AA64DFR0_EL1
KVM: arm64: selftests: Stop unnecessary test stage tracking of debug-exceptions
KVM: arm64: selftests: Add helpers to enable debug exceptions
KVM: arm64: selftests: Remove the hard-coded {b,w}pn#0 from debug-exceptions
KVM: arm64: selftests: Add write_dbg{b,w}{c,v}r helpers in debug-exceptions
KVM: arm64: selftests: Use FIELD_GET() to extract ID register fields
Signed-off-by: Marc Zyngier <maz@kernel.org>
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* kvm-arm64/selftest/memslot-fixes:
: .
: KVM memslot selftest fixes for non-4kB page sizes, courtesy
: of Gavin Shan. From the cover letter:
:
: "kvm/selftests/memslots_perf_test doesn't work with 64KB-page-size-host
: and 4KB-page-size-guest on aarch64. In the implementation, the host and
: guest page size have been hardcoded to 4KB. It's ovbiously not working
: on aarch64 which supports 4KB, 16KB, 64KB individually on host and guest.
:
: This series tries to fix it. After the series is applied, the test runs
: successfully with 64KB-page-size-host and 4KB-page-size-guest."
: .
KVM: selftests: memslot_perf_test: Report optimal memory slots
KVM: selftests: memslot_perf_test: Consolidate memory
KVM: selftests: memslot_perf_test: Support variable guest page size
KVM: selftests: memslot_perf_test: Probe memory slots for once
KVM: selftests: memslot_perf_test: Consolidate loop conditions in prepare_vm()
KVM: selftests: memslot_perf_test: Use data->nslots in prepare_vm()
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Fix the bogus masking when computing the period of a 64bit counter
with 32bit overflow. It really should be treated like a 32bit counter
for the purpose of the period.
Reported-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/Y4jbosgHbUDI0WF4@google.com
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Pull Xen-for-KVM changes from David Woodhouse:
* add support for 32-bit guests in SCHEDOP_poll
* the rest of the gfn-to-pfn cache API cleanup
"I still haven't reinstated the last of those patches to make gpc->len
immutable."
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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CPUID.80000021H:EAX[bit 9] indicates that the SMM_CTL MSR (0xc0010116) is
not supported. This defeature can be advertised by KVM_GET_SUPPORTED_CPUID
regardless of whether or not the host enumerates it; currently it will be
included only if the host enumerates at least leaf 8000001DH, due to a
preexisting bug in QEMU that KVM has to work around (commit f751d8eac176,
"KVM: x86: work around QEMU issue with synthetic CPUID leaves", 2022-04-29).
Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <20221007221644.138355-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Several symbols are not used by vendor modules but still exported.
Removing them ensures that new coupling between kvm.ko and kvm-*.ko
is noticed and reviewed.
Co-developed-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Like Xu <like.xu.linux@gmail.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <like.xu.linux@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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There is a spelling mistake in some help text. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Message-Id: <20221201091354.1613652-1-colin.i.king@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Convert {clear,set}_bit() to atomics as KVM's ucall implementation relies
on clear_bit() being atomic, they are defined in atomic.h, and the same
helpers in the kernel proper are atomic.
KVM's ucall infrastructure is the only user of clear_bit() in tools/, and
there are no true set_bit() users. tools/testing/nvdimm/ does make heavy
use of set_bit(), but that code builds into a kernel module of sorts, i.e.
pulls in all of the kernel's header and so is already getting the kernel's
atomic set_bit().
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
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Drop the "atomic_" prefix from tools' atomic_test_and_set_bit() to
match the kernel nomenclature where test_and_set_bit() is atomic,
and __test_and_set_bit() provides the non-atomic variant.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Drop tools' non-atomic test_and_set_bit() and test_and_clear_bit() helpers
now that all users are gone. The names will be claimed in the future for
atomic versions.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-8-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Use the dedicated non-atomic helpers for {clear,set}_bit() and their
test variants, i.e. the double-underscore versions. Depsite being
defined in atomic.h, and despite the kernel versions being atomic in the
kernel, tools' {clear,set}_bit() helpers aren't actually atomic. Move
to the double-underscore versions so that the versions that are expected
to be atomic (for kernel developers) can be made atomic without affecting
users that don't want atomic operations.
Leave the usage in ucall_free() as-is, it's the one place in tools/ that
actually wants/needs atomic behavior.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Use the dedicated non-atomic helpers for {clear,set}_bit() and their
test variants, i.e. the double-underscore versions. Depsite being
defined in atomic.h, and despite the kernel versions being atomic in the
kernel, tools' {clear,set}_bit() helpers aren't actually atomic. Move
to the double-underscore versions so that the versions that are expected
to be atomic (for kernel developers) can be made atomic without affecting
users that don't want atomic operations.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Message-Id: <20221119013450.2643007-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Take @bit as an unsigned long instead of a signed int in clear_bit() and
set_bit() so that they match the double-underscore versions, __clear_bit()
and __set_bit(). This will allow converting users that really don't want
atomic operations to the double-underscores without introducing a
functional change, which will in turn allow making {clear,set}_bit()
atomic (as advertised).
Practically speaking, this _should_ have no functional impact. KVM's
selftests usage is either hardcoded (Hyper-V tests) or is artificially
limited (arch_timer test and dirty_log test). In KVM, dirty_log test is
the only mildly interesting case as it's use indirectly restricted to
unsigned 32-bit values, but in theory it could generate a negative value
when cast to a signed int. But in that case, taking an "unsigned long"
is actually a bug fix.
Perf's usage is more difficult to audit, but any code that is affected
by the switch is likely already broken. perf_header__{set,clear}_feat()
and perf_file_header__read() effectively use only hardcoded enums with
small, positive values, atom_new() passes an unsigned long, but its value
is capped at 128 via NR_ATOM_PER_PAGE, etc...
The only real potential for breakage is in the perf flows that take a
"cpu", but it's unlikely perf is subtly relying on a negative index into
bitmaps, e.g. "cpu" can be "-1", but only as "not valid" placeholder.
Note, tools/testing/nvdimm/ makes heavy use of set_bit(), but that code
builds into a kernel module of sorts, i.e. pulls in all of the kernel's
header and so is getting the kernel's atomic set_bit(). The NVDIMM test
usage of atomics is likely unnecessary, e.g. ndtest_dimm_register() sets
bits in a local variable, but that's neither here nor there as far as
this change is concerned.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Add a new ucall hook, GUEST_UCALL_NONE(), to allow tests to make ucalls
without allocating a ucall struct, and use it to enable single-step
in ARM's debug-exceptions test. Like the disable single-step path, the
enabling path also needs to ensure that no exclusive access sequences are
attempted after enabling single-step, as the exclusive monitor is cleared
on ERET from the debug exception taken to EL2.
The test currently "works" because clear_bit() isn't actually an atomic
operation... yet.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221119013450.2643007-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When a VM reboots itself, the reset process will result in
an ioctl(KVM_SET_LAPIC, ...) to disable x2APIC mode and set
the xAPIC id of the vCPU to its default value, which is the
vCPU id.
That will be handled in KVM as follows:
kvm_vcpu_ioctl_set_lapic
kvm_apic_set_state
kvm_lapic_set_base => disable X2APIC mode
kvm_apic_state_fixup
kvm_lapic_xapic_id_updated
kvm_xapic_id(apic) != apic->vcpu->vcpu_id
kvm_set_apicv_inhibit(APICV_INHIBIT_REASON_APIC_ID_MODIFIED)
memcpy(vcpu->arch.apic->regs, s->regs, sizeof(*s)) => update APIC_ID
When kvm_apic_set_state invokes kvm_lapic_set_base to disable
x2APIC mode, the old 32-bit x2APIC id is still present rather
than the 8-bit xAPIC id. kvm_lapic_xapic_id_updated will set the
APICV_INHIBIT_REASON_APIC_ID_MODIFIED bit and disable APICv/x2AVIC.
Instead, kvm_lapic_xapic_id_updated must be called after APIC_ID is
changed.
In fact, this fixes another small issue in the code in that
potential changes to a vCPU's xAPIC ID need not be tracked for
KVM_GET_LAPIC.
Fixes: 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base")
Signed-off-by: Yuan ZhaoXiong <yuanzhaoxiong@baidu.com>
Message-Id: <1669984574-32692-1-git-send-email-yuanzhaoxiong@baidu.com>
Cc: stable@vger.kernel.org
Reported-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Remove a comment about KVM_REQ_UNHALT being set by kvm_vcpu_check_block()
that was missed when KVM_REQ_UNHALT was dropped.
Fixes: c59fb1275838 ("KVM: remove KVM_REQ_UNHALT")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221201220433.31366-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
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Misc KVM x86 fixes and cleanups for 6.2:
- One-off fixes for various emulation flows (SGX, VMXON, NRIPS=0).
- Reinstate IBPB on emulated VM-Exit that was incorrectly dropped a few
years back when eliminating unnecessary barriers when switching between
vmcs01 and vmcs02.
- Clean up the MSR filter docs.
- Clean up vmread_error_trampoline() to make it more obvious that params
must be passed on the stack, even for x86-64.
- Let userspace set all supported bits in MSR_IA32_FEAT_CTL irrespective
of the current guest CPUID.
- Fudge around a race with TSC refinement that results in KVM incorrectly
thinking a guest needs TSC scaling when running on a CPU with a
constant TSC, but no hardware-enumerated TSC frequency.
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KVM selftests fixes for 6.2
- Fix an inverted check in the access tracking perf test, and restore
support for asserting that there aren't too many idle pages when
running on bare metal.
- Fix an ordering issue in the AMX test introduced by recent conversions
to use kvm_cpu_has(), and harden the code to guard against similar bugs
in the future. Anything that tiggers caching of KVM's supported CPUID,
kvm_cpu_has() in this case, effectively hides opt-in XSAVE features if
the caching occurs before the test opts in via prctl().
- Fix build errors that occur in certain setups (unsure exactly what is
unique about the problematic setup) due to glibc overriding
static_assert() to a variant that requires a custom message.
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The ioctls are missing an architecture property that is present in others.
Suggested-by: Sergio Lopez Pascual <slp@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Message-Id: <20221202105011.185147-5-javierm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
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There are still references to the removed kvm_memory_region data structure
but the doc and comments should mention struct kvm_userspace_memory_region
instead, since that is what's used by the ioctl that replaced the old one
and this data structure support the same set of flags.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Message-Id: <20221202105011.185147-4-javierm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
The documentation says that the ioctl has been deprecated, but it has been
actually removed and the remaining references are just left overs.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Message-Id: <20221202105011.185147-3-javierm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
The documentation says that the ioctl has been deprecated, but it has been
actually removed and the remaining references are just left overs.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Message-Id: <20221202105011.185147-2-javierm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
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Define and use kvm_static_assert() in the common KVM selftests headers to
provide deterministic behavior, and to allow creating static asserts
without dummy messages.
The kernel's static_assert() makes the message param optional, and on the
surface, tools/include/linux/build_bug.h appears to follow suit. However,
glibc may override static_assert() and redefine it as a direct alias of
_Static_assert(), which makes the message parameter mandatory. This leads
to non-deterministic behavior as KVM selftests code that utilizes
static_assert() without a custom message may or not compile depending on
the order of includes. E.g. recently added asserts in
x86_64/processor.h fail on some systems with errors like
In file included from lib/memstress.c:11:0:
include/x86_64/processor.h: In function ‘this_cpu_has_p’:
include/x86_64/processor.h:193:34: error: expected ‘,’ before ‘)’ token
static_assert(low_bit < high_bit); \
^
due to _Static_assert() expecting a comma before a message. The "message
optional" version of static_assert() uses macro magic to strip away the
comma when presented with empty an __VA_ARGS__
#ifndef static_assert
#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
#endif // static_assert
and effectively generates "_Static_assert(expr, #expr)".
The incompatible version of static_assert() gets defined by this snippet
in /usr/include/assert.h:
#if defined __USE_ISOC11 && !defined __cplusplus
# undef static_assert
# define static_assert _Static_assert
#endif
which yields "_Static_assert(expr)" and thus fails as above.
KVM selftests don't actually care about using C11, but __USE_ISOC11 gets
defined because of _GNU_SOURCE, which many tests do #define. _GNU_SOURCE
triggers a massive pile of defines in /usr/include/features.h, including
_ISOC11_SOURCE:
/* If _GNU_SOURCE was defined by the user, turn on all the other features. */
#ifdef _GNU_SOURCE
# undef _ISOC95_SOURCE
# define _ISOC95_SOURCE 1
# undef _ISOC99_SOURCE
# define _ISOC99_SOURCE 1
# undef _ISOC11_SOURCE
# define _ISOC11_SOURCE 1
# undef _POSIX_SOURCE
# define _POSIX_SOURCE 1
# undef _POSIX_C_SOURCE
# define _POSIX_C_SOURCE 200809L
# undef _XOPEN_SOURCE
# define _XOPEN_SOURCE 700
# undef _XOPEN_SOURCE_EXTENDED
# define _XOPEN_SOURCE_EXTENDED 1
# undef _LARGEFILE64_SOURCE
# define _LARGEFILE64_SOURCE 1
# undef _DEFAULT_SOURCE
# define _DEFAULT_SOURCE 1
# undef _ATFILE_SOURCE
# define _ATFILE_SOURCE 1
#endif
which further down in /usr/include/features.h leads to:
/* This is to enable the ISO C11 extension. */
#if (defined _ISOC11_SOURCE \
|| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
# define __USE_ISOC11 1
#endif
To make matters worse, /usr/include/assert.h doesn't guard against
multiple inclusion by turning itself into a nop, but instead #undefs a
few macros and continues on. As a result, it's all but impossible to
ensure the "message optional" version of static_assert() will actually be
used, e.g. explicitly including assert.h and #undef'ing static_assert()
doesn't work as a later inclusion of assert.h will again redefine its
version.
#ifdef _ASSERT_H
# undef _ASSERT_H
# undef assert
# undef __ASSERT_VOID_CAST
# ifdef __USE_GNU
# undef assert_perror
# endif
#endif /* assert.h */
#define _ASSERT_H 1
#include <features.h>
Fixes: fcba483e8246 ("KVM: selftests: Sanity check input to ioctls() at build time")
Fixes: ee3795536664 ("KVM: selftests: Refactor X86_FEATURE_* framework to prep for X86_PROPERTY_*")
Fixes: 53a7dc0f215e ("KVM: selftests: Add X86_PROPERTY_* framework to retrieve CPUID values")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221122013309.1872347-1-seanjc@google.com
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