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authorLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 13:31:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-21 13:31:43 -0800
commit3e10585335b7967326ca7b4118cada0d2d00a2ab (patch)
treee1655bc4f093f7de3a54dc3b2d83a54159aca10b /Documentation
parent9c5b80b795e9c847a7b7f5e63c6bcf07873fbcdf (diff)
parent8c6e67bec3192f16fa624203c8131e10cc4814ba (diff)
downloadlinux-3e10585335b7967326ca7b4118cada0d2d00a2ab.tar.bz2
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini: "x86: - Support for userspace to emulate Xen hypercalls - Raise the maximum number of user memslots - Scalability improvements for the new MMU. Instead of the complex "fast page fault" logic that is used in mmu.c, tdp_mmu.c uses an rwlock so that page faults are concurrent, but the code that can run against page faults is limited. Right now only page faults take the lock for reading; in the future this will be extended to some cases of page table destruction. I hope to switch the default MMU around 5.12-rc3 (some testing was delayed due to Chinese New Year). - Cleanups for MAXPHYADDR checks - Use static calls for vendor-specific callbacks - On AMD, use VMLOAD/VMSAVE to save and restore host state - Stop using deprecated jump label APIs - Workaround for AMD erratum that made nested virtualization unreliable - Support for LBR emulation in the guest - Support for communicating bus lock vmexits to userspace - Add support for SEV attestation command - Miscellaneous cleanups PPC: - Support for second data watchpoint on POWER10 - Remove some complex workarounds for buggy early versions of POWER9 - Guest entry/exit fixes ARM64: - Make the nVHE EL2 object relocatable - Cleanups for concurrent translation faults hitting the same page - Support for the standard TRNG hypervisor call - A bunch of small PMU/Debug fixes - Simplification of the early init hypercall handling Non-KVM changes (with acks): - Detection of contended rwlocks (implemented only for qrwlocks, because KVM only needs it for x86) - Allow __DISABLE_EXPORTS from assembly code - Provide a saner follow_pfn replacements for modules" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (192 commits) KVM: x86/xen: Explicitly pad struct compat_vcpu_info to 64 bytes KVM: selftests: Don't bother mapping GVA for Xen shinfo test KVM: selftests: Fix hex vs. decimal snafu in Xen test KVM: selftests: Fix size of memslots created by Xen tests KVM: selftests: Ignore recently added Xen tests' build output KVM: selftests: Add missing header file needed by xAPIC IPI tests KVM: selftests: Add operand to vmsave/vmload/vmrun in svm.c KVM: SVM: Make symbol 'svm_gp_erratum_intercept' static locking/arch: Move qrwlock.h include after qspinlock.h KVM: PPC: Book3S HV: Fix host radix SLB optimisation with hash guests KVM: PPC: Book3S HV: Ensure radix guest has no SLB entries KVM: PPC: Don't always report hash MMU capability for P9 < DD2.2 KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path KVM: PPC: remove unneeded semicolon KVM: PPC: Book3S HV: Use POWER9 SLBIA IH=6 variant to clear SLB KVM: PPC: Book3S HV: No need to clear radix host SLB before loading HPT guest KVM: PPC: Book3S HV: Fix radix guest SLB side channel KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWR KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWR ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/virt/kvm/amd-memory-encryption.rst21
-rw-r--r--Documentation/virt/kvm/api.rst228
-rw-r--r--Documentation/virt/kvm/locking.rst9
3 files changed, 249 insertions, 9 deletions
diff --git a/Documentation/virt/kvm/amd-memory-encryption.rst b/Documentation/virt/kvm/amd-memory-encryption.rst
index 09a8f2a34e39..469a6308765b 100644
--- a/Documentation/virt/kvm/amd-memory-encryption.rst
+++ b/Documentation/virt/kvm/amd-memory-encryption.rst
@@ -263,6 +263,27 @@ Returns: 0 on success, -negative on error
__u32 trans_len;
};
+10. KVM_SEV_GET_ATTESTATION_REPORT
+----------------------------------
+
+The KVM_SEV_GET_ATTESTATION_REPORT command can be used by the hypervisor to query the attestation
+report containing the SHA-256 digest of the guest memory and VMSA passed through the KVM_SEV_LAUNCH
+commands and signed with the PEK. The digest returned by the command should match the digest
+used by the guest owner with the KVM_SEV_LAUNCH_MEASURE.
+
+Parameters (in): struct kvm_sev_attestation
+
+Returns: 0 on success, -negative on error
+
+::
+
+ struct kvm_sev_attestation_report {
+ __u8 mnonce[16]; /* A random mnonce that will be placed in the report */
+
+ __u64 uaddr; /* userspace address where the report should be copied */
+ __u32 len;
+ };
+
References
==========
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 99ceb978c8b0..45fd862ac128 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -960,6 +960,14 @@ memory.
__u8 pad2[30];
};
+If the KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag is returned from the
+KVM_CAP_XEN_HVM check, it may be set in the flags field of this ioctl.
+This requests KVM to generate the contents of the hypercall page
+automatically; hypercalls will be intercepted and passed to userspace
+through KVM_EXIT_XEN. In this case, all of the blob size and address
+fields must be zero.
+
+No other flags are currently valid in the struct kvm_xen_hvm_config.
4.29 KVM_GET_CLOCK
------------------
@@ -2268,6 +2276,8 @@ registers, find a list below:
PPC KVM_REG_PPC_PSSCR 64
PPC KVM_REG_PPC_DEC_EXPIRY 64
PPC KVM_REG_PPC_PTCR 64
+ PPC KVM_REG_PPC_DAWR1 64
+ PPC KVM_REG_PPC_DAWRX1 64
PPC KVM_REG_PPC_TM_GPR0 64
...
PPC KVM_REG_PPC_TM_GPR31 64
@@ -4831,6 +4841,101 @@ into user space.
If a vCPU is in running state while this ioctl is invoked, the vCPU may
experience inconsistent filtering behavior on MSR accesses.
+4.127 KVM_XEN_HVM_SET_ATTR
+--------------------------
+
+:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
+:Architectures: x86
+:Type: vm ioctl
+:Parameters: struct kvm_xen_hvm_attr
+:Returns: 0 on success, < 0 on error
+
+::
+
+ struct kvm_xen_hvm_attr {
+ __u16 type;
+ __u16 pad[3];
+ union {
+ __u8 long_mode;
+ __u8 vector;
+ struct {
+ __u64 gfn;
+ } shared_info;
+ __u64 pad[4];
+ } u;
+ };
+
+type values:
+
+KVM_XEN_ATTR_TYPE_LONG_MODE
+ Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This
+ determines the layout of the shared info pages exposed to the VM.
+
+KVM_XEN_ATTR_TYPE_SHARED_INFO
+ Sets the guest physical frame number at which the Xen "shared info"
+ page resides. Note that although Xen places vcpu_info for the first
+ 32 vCPUs in the shared_info page, KVM does not automatically do so
+ and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO be used
+ explicitly even when the vcpu_info for a given vCPU resides at the
+ "default" location in the shared_info page. This is because KVM is
+ not aware of the Xen CPU id which is used as the index into the
+ vcpu_info[] array, so cannot know the correct default location.
+
+KVM_XEN_ATTR_TYPE_UPCALL_VECTOR
+ Sets the exception vector used to deliver Xen event channel upcalls.
+
+4.128 KVM_XEN_HVM_GET_ATTR
+--------------------------
+
+:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
+:Architectures: x86
+:Type: vm ioctl
+:Parameters: struct kvm_xen_hvm_attr
+:Returns: 0 on success, < 0 on error
+
+Allows Xen VM attributes to be read. For the structure and types,
+see KVM_XEN_HVM_SET_ATTR above.
+
+4.129 KVM_XEN_VCPU_SET_ATTR
+---------------------------
+
+:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
+:Architectures: x86
+:Type: vcpu ioctl
+:Parameters: struct kvm_xen_vcpu_attr
+:Returns: 0 on success, < 0 on error
+
+::
+
+ struct kvm_xen_vcpu_attr {
+ __u16 type;
+ __u16 pad[3];
+ union {
+ __u64 gpa;
+ __u64 pad[4];
+ } u;
+ };
+
+type values:
+
+KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO
+ Sets the guest physical address of the vcpu_info for a given vCPU.
+
+KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO
+ Sets the guest physical address of an additional pvclock structure
+ for a given vCPU. This is typically used for guest vsyscall support.
+
+4.130 KVM_XEN_VCPU_GET_ATTR
+---------------------------
+
+:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO
+:Architectures: x86
+:Type: vcpu ioctl
+:Parameters: struct kvm_xen_vcpu_attr
+:Returns: 0 on success, < 0 on error
+
+Allows Xen vCPU attributes to be read. For the structure and types,
+see KVM_XEN_VCPU_SET_ATTR above.
5. The kvm_run structure
========================
@@ -4893,9 +4998,11 @@ local APIC is not used.
__u16 flags;
More architecture-specific flags detailing state of the VCPU that may
-affect the device's behavior. The only currently defined flag is
-KVM_RUN_X86_SMM, which is valid on x86 machines and is set if the
-VCPU is in system management mode.
+affect the device's behavior. Current defined flags:
+ /* x86, set if the VCPU is in system management mode */
+ #define KVM_RUN_X86_SMM (1 << 0)
+ /* x86, set if bus lock detected in VM */
+ #define KVM_RUN_BUS_LOCK (1 << 1)
::
@@ -4996,13 +5103,18 @@ to the byte array.
.. note::
- For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR,
+ For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN,
KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding
operations are complete (and guest state is consistent) only after userspace
has re-entered the kernel with KVM_RUN. The kernel side will first finish
- incomplete operations and then check for pending signals. Userspace
- can re-enter the guest with an unmasked signal pending to complete
- pending operations.
+ incomplete operations and then check for pending signals.
+
+ The pending state of the operation is not preserved in state which is
+ visible to userspace, thus userspace should ensure that the operation is
+ completed before performing a live migration. Userspace can re-enter the
+ guest with an unmasked signal pending or with the immediate_exit field set
+ to complete pending operations without allowing any further instructions
+ to be executed.
::
@@ -5329,6 +5441,34 @@ vCPU execution. If the MSR write was unsuccessful, user space also sets the
::
+
+ struct kvm_xen_exit {
+ #define KVM_EXIT_XEN_HCALL 1
+ __u32 type;
+ union {
+ struct {
+ __u32 longmode;
+ __u32 cpl;
+ __u64 input;
+ __u64 result;
+ __u64 params[6];
+ } hcall;
+ } u;
+ };
+ /* KVM_EXIT_XEN */
+ struct kvm_hyperv_exit xen;
+
+Indicates that the VCPU exits into userspace to process some tasks
+related to Xen emulation.
+
+Valid values for 'type' are:
+
+ - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall.
+ Userspace is expected to place the hypercall result into the appropriate
+ field before invoking KVM_RUN again.
+
+::
+
/* Fix the size of the union. */
char padding[256];
};
@@ -6038,6 +6178,53 @@ KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications which user space
can then handle to implement model specific MSR handling and/or user notifications
to inform a user that an MSR was not handled.
+7.22 KVM_CAP_X86_BUS_LOCK_EXIT
+-------------------------------
+
+:Architectures: x86
+:Target: VM
+:Parameters: args[0] defines the policy used when bus locks detected in guest
+:Returns: 0 on success, -EINVAL when args[0] contains invalid bits
+
+Valid bits in args[0] are::
+
+ #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0)
+ #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1)
+
+Enabling this capability on a VM provides userspace with a way to select
+a policy to handle the bus locks detected in guest. Userspace can obtain
+the supported modes from the result of KVM_CHECK_EXTENSION and define it
+through the KVM_ENABLE_CAP.
+
+KVM_BUS_LOCK_DETECTION_OFF and KVM_BUS_LOCK_DETECTION_EXIT are supported
+currently and mutually exclusive with each other. More bits can be added in
+the future.
+
+With KVM_BUS_LOCK_DETECTION_OFF set, bus locks in guest will not cause vm exits
+so that no additional actions are needed. This is the default mode.
+
+With KVM_BUS_LOCK_DETECTION_EXIT set, vm exits happen when bus lock detected
+in VM. KVM just exits to userspace when handling them. Userspace can enforce
+its own throttling or other policy based mitigations.
+
+This capability is aimed to address the thread that VM can exploit bus locks to
+degree the performance of the whole system. Once the userspace enable this
+capability and select the KVM_BUS_LOCK_DETECTION_EXIT mode, KVM will set the
+KVM_RUN_BUS_LOCK flag in vcpu-run->flags field and exit to userspace. Concerning
+the bus lock vm exit can be preempted by a higher priority VM exit, the exit
+notifications to userspace can be KVM_EXIT_BUS_LOCK or other reasons.
+KVM_RUN_BUS_LOCK flag is used to distinguish between them.
+
+7.22 KVM_CAP_PPC_DAWR1
+----------------------
+
+:Architectures: ppc
+:Parameters: none
+:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR
+
+This capability can be used to check / enable 2nd DAWR feature provided
+by POWER10 processor.
+
8. Other capabilities.
======================
@@ -6415,7 +6602,6 @@ guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf
(0x40000001). Otherwise, a guest may use the paravirtual features
regardless of what has actually been exposed through the CPUID leaf.
-
8.29 KVM_CAP_DIRTY_LOG_RING
---------------------------
@@ -6502,3 +6688,29 @@ KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG. After enabling
KVM_CAP_DIRTY_LOG_RING with an acceptable dirty ring size, the virtual
machine will switch to ring-buffer dirty page tracking and further
KVM_GET_DIRTY_LOG or KVM_CLEAR_DIRTY_LOG ioctls will fail.
+
+8.30 KVM_CAP_XEN_HVM
+--------------------
+
+:Architectures: x86
+
+This capability indicates the features that Xen supports for hosting Xen
+PVHVM guests. Valid flags are::
+
+ #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0)
+ #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1)
+ #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2)
+
+The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG
+ioctl is available, for the guest to set its hypercall page.
+
+If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be
+provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page
+contents, to request that KVM generate hypercall page content automatically
+and also enable interception of guest hypercalls with KVM_EXIT_XEN.
+
+The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the
+KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and
+KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors
+for event channel upcalls when the evtchn_upcall_pending field of a vcpu's
+vcpu_info is set.
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst
index b21a34c34a21..0aa4817b466d 100644
--- a/Documentation/virt/kvm/locking.rst
+++ b/Documentation/virt/kvm/locking.rst
@@ -16,7 +16,14 @@ The acquisition orders for mutexes are as follows:
- kvm->slots_lock is taken outside kvm->irq_lock, though acquiring
them together is quite rare.
-On x86, vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock.
+On x86:
+
+- vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock
+
+- kvm->arch.mmu_lock is an rwlock. kvm->arch.tdp_mmu_pages_lock is
+ taken inside kvm->arch.mmu_lock, and cannot be taken without already
+ holding kvm->arch.mmu_lock (typically with ``read_lock``, otherwise
+ there's no need to take kvm->arch.tdp_mmu_pages_lock at all).
Everything else is a leaf: no other lock is taken inside the critical
sections.