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2015-11-10KVM: x86: Add a common TSC scaling functionHaozhong Zhang5-45/+97
VMX and SVM calculate the TSC scaling ratio in a similar logic, so this patch generalizes it to a common TSC scaling function. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> [Inline the multiplication and shift steps into mul_u64_u64_shr. Remove BUG_ON. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-10KVM: x86: Add a common TSC scaling ratio field in kvm_vcpu_archHaozhong Zhang3-16/+20
This patch moves the field of TSC scaling ratio from the architecture struct vcpu_svm to the common struct kvm_vcpu_arch. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-10KVM: x86: Collect information for setting TSC scaling ratioHaozhong Zhang3-0/+11
The number of bits of the fractional part of the 64-bit TSC scaling ratio in VMX and SVM is different. This patch makes the architecture code to collect the number of fractional bits and other related information into variables that can be accessed in the common code. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-10KVM: x86: declare a few variables as __read_mostlyPaolo Bonzini2-9/+7
These include module parameters and variables that are set by kvm_x86_ops->hardware_setup. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-10KVM: x86: merge handle_mmio_page_fault and handle_mmio_page_fault_commonPaolo Bonzini4-21/+10
They are exactly the same, except that handle_mmio_page_fault has an unused argument and a call to WARN_ON. Remove the unused argument from the callers, and move the warning to (the former) handle_mmio_page_fault_common. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-05KVM: VMX: Fix commit which broke PMLKai Huang1-13/+11
I found PML was broken since below commit: commit feda805fe7c4ed9cf78158e73b1218752e3b4314 Author: Xiao Guangrong <guangrong.xiao@linux.intel.com> Date: Wed Sep 9 14:05:55 2015 +0800 KVM: VMX: unify SECONDARY_VM_EXEC_CONTROL update Unify the update in vmx_cpuid_update() Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> [Rewrite to use vmcs_set_secondary_exec_control. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> The reason is in above commit vmx_cpuid_update calls vmx_secondary_exec_control, in which currently SECONDARY_EXEC_ENABLE_PML bit is cleared unconditionally (as PML is enabled in creating vcpu). Therefore if vcpu_cpuid_update is called after vcpu is created, PML will be disabled unexpectedly while log-dirty code still thinks PML is used. Fix this by clearing SECONDARY_EXEC_ENABLE_PML in vmx_secondary_exec_control only when PML is not supported or not enabled (!enable_pml). This is more reasonable as PML is currently either always enabled or disabled. With this explicit updating SECONDARY_EXEC_ENABLE_PML in vmx_enable{disable}_pml is not needed so also rename vmx_enable{disable}_pml to vmx_create{destroy}_pml_buffer. Fixes: feda805fe7c4ed9cf78158e73b1218752e3b4314 Signed-off-by: Kai Huang <kai.huang@linux.intel.com> [While at it, change a wrong ASSERT to an "if". The condition can happen if creating the VCPU fails with ENOMEM. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: obey KVM_X86_QUIRK_CD_NW_CLEARED in kvm_set_cr0()Laszlo Ersek1-1/+3
Commit b18d5431acc7 ("KVM: x86: fix CR0.CD virtualization") was technically correct, but it broke OVMF guests by slowing down various parts of the firmware. Commit fb279950ba02 ("KVM: vmx: obey KVM_QUIRK_CD_NW_CLEARED") quirked the first function modified by b18d5431acc7, vmx_get_mt_mask(), for OVMF's sake. This restored the speed of the OVMF code that runs before PlatformPei (including the memory intensive LZMA decompression in SEC). This patch extends the quirk to the second function modified by b18d5431acc7, kvm_set_cr0(). It eliminates the intrusive slowdown that hits the EFI_MP_SERVICES_PROTOCOL implementation of edk2's UefiCpuPkg/CpuDxe -- which is built into OVMF --, when CpuDxe starts up all APs at once for initialization, in order to count them. We also carry over the kvm_arch_has_noncoherent_dma() sub-condition from the other half of the original commit b18d5431acc7. Fixes: b18d5431acc7a2fd22767925f3a6f597aa4bd29e Cc: stable@vger.kernel.org Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Tested-by: Janusz Mocek <januszmk6@gmail.com> Signed-off-by: Laszlo Ersek <lersek@redhat.com># Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: allow RSM from 64-bit modePaolo Bonzini1-5/+25
The SDM says that exiting system management mode from 64-bit mode is invalid, but that would be too good to be true. But actually, most of the code is already there to support exiting from compat mode (EFER.LME=1, EFER.LMA=0). Getting all the way from 64-bit mode to real mode only requires clearing CS.L and CR4.PCIDE. Cc: stable@vger.kernel.org Fixes: 660a5d517aaab9187f93854425c4c63f4a09195c Tested-by: Laszlo Ersek <lersek@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: VMX: fix SMEP and SMAP without EPTRadim Krčmář1-9/+10
The comment in code had it mostly right, but we enable paging for emulated real mode regardless of EPT. Without EPT (which implies emulated real mode), secondary VCPUs won't start unless we disable SM[AE]P when the guest doesn't use paging. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: move kvm_set_irq_inatomic to legacy device assignmentPaolo Bonzini3-35/+37
The function is not used outside device assignment, and kvm_arch_set_irq_inatomic has a different prototype. Move it here and make it static to avoid confusion. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: device assignment: remove pointless #ifdefsPaolo Bonzini1-25/+0
The symbols are always defined. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: merge kvm_arch_set_irq with kvm_set_msi_inatomicPaolo Bonzini3-17/+15
We do not want to do too much work in atomic context, in particular not walking all the VCPUs of the virtual machine. So we want to distinguish the architecture-specific injection function for irqfd from kvm_set_msi. Since it's still empty, reuse the newly added kvm_arch_set_irq and rename it to kvm_arch_set_irq_inatomic. Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: zero apic_arb_prio on resetRadim Krčmář1-0/+2
BSP doesn't get INIT so its apic_arb_prio isn't zeroed after reboot. BSP won't get lowest priority interrupts until other VCPUs get enough interrupts to match their pre-reboot apic_arb_prio. That behavior doesn't fit into KVM's round-robin-like interpretation of lowest priority delivery ... userspace should KVM_SET_LAPIC on reset, so just zero apic_arb_prio there. Reported-by: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04drivers/hv: share Hyper-V SynIC constants with userspaceAndrey Smetanin3-5/+13
Moved Hyper-V synic contants from guest Hyper-V drivers private header into x86 arch uapi Hyper-V header. Added Hyper-V synic msr's flags into x86 arch uapi Hyper-V header. Signed-off-by: Andrey Smetanin <asmetanin@virtuozzo.com> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Vitaly Kuznetsov <vkuznets@redhat.com> CC: "K. Y. Srinivasan" <kys@microsoft.com> CC: Gleb Natapov <gleb@kernel.org> CC: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: handle SMBASE as physical address in RSMRadim Krčmář1-4/+3
GET_SMSTATE depends on real mode to ensure that smbase+offset is treated as a physical address, which has already caused a bug after shuffling the code. Enforce physical addressing. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reported-by: Laszlo Ersek <lersek@redhat.com> Tested-by: Laszlo Ersek <lersek@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: add read_phys to x86_emulate_opsRadim Krčmář2-0/+20
We want to read the physical memory when emulating RSM. X86EMUL_IO_NEEDED is returned on all errors for consistency with other helpers. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Tested-by: Laszlo Ersek <lersek@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: x86: removing unused variableSaurabh Sengar1-11/+5
removing unused variables, found by coccinelle Signed-off-by: Saurabh Sengar <saurabh.truth@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04KVM: don't pointlessly leave KVM_COMPAT=y in non-KVM configsJan Beulich1-1/+1
The symbol was missing a KVM dependency. Signed-off-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-11-04Merge tag 'kvm-arm-for-4.4' of ↵Paolo Bonzini25-297/+676
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/ARM Changes for v4.4-rc1 Includes a number of fixes for the arch-timer, introducing proper level-triggered semantics for the arch-timers, a series of patches to synchronously halt a guest (prerequisite for IRQ forwarding), some tracepoint improvements, a tweak for the EL2 panic handlers, some more VGIC cleanups getting rid of redundant state, and finally a stylistic change that gets rid of some ctags warnings. Conflicts: arch/x86/include/asm/kvm_host.h
2015-11-04KVM: arm/arm64: Merge vgic_set_lr() and vgic_sync_lr_elrsr()Pavel Fedin4-23/+2
Now we see that vgic_set_lr() and vgic_sync_lr_elrsr() are always used together. Merge them into one function, saving from second vgic_ops dereferencing every time. Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-04KVM: arm/arm64: Clean up vgic_retire_lr() and surroundingsPavel Fedin1-27/+10
1. Remove unnecessary 'irq' argument, because irq number can be retrieved from the LR. 2. Since cff9211eb1a1f58ce7f5a2d596b617928fd4be0e ("arm/arm64: KVM: Fix arch timer behavior for disabled interrupts ") LR_STATE_PENDING is queued back by vgic_retire_lr() itself. Also, it clears vlr.state itself. Therefore, we remove the same, now duplicated, check with all accompanying bit manipulations from vgic_unqueue_irqs(). 3. vgic_retire_lr() is always accompanied by vgic_irq_clear_queued(). Since it already does more than just clearing the LR, move vgic_irq_clear_queued() inside of it. Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-04KVM: arm/arm64: Optimize away redundant LR trackingPavel Fedin4-44/+17
Currently we use vgic_irq_lr_map in order to track which LRs hold which IRQs, and lr_used bitmap in order to track which LRs are used or free. vgic_irq_lr_map is actually used only for piggy-back optimization, and can be easily replaced by iteration over lr_used. This is good because in future, when LPI support is introduced, number of IRQs will grow up to at least 16384, while numbers from 1024 to 8192 are never going to be used. This would be a huge memory waste. In its turn, lr_used is also completely redundant since ae705930fca6322600690df9dc1c7d0516145a93 ("arm/arm64: KVM: Keep elrsr/aisr in sync with software model"), because together with lr_used we also update elrsr. This allows to easily replace lr_used with elrsr, inverting all conditions (because in elrsr '1' means 'free'). Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-11-02Merge branch 'kvm-ppc-next' of ↵Paolo Bonzini9-11/+63
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into HEAD There's nothing much in the way of new features this time; it's mostly bug fixes, plus Nikunj has implemented support for KVM_CAP_NR_MEMSLOTS.
2015-11-02Merge tag 'kvm-s390-next-20151028' of ↵Paolo Bonzini2-26/+28
git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Bugfix and cleanups There is one important bug fix for a potential memory corruption and/or guest errors for guests with 63 or 64 vCPUs. This fix would qualify for 4.3 but is some days too late giving that we are about to release 4.3. Given that this patch is cc stable >= 3.15 anyway, we can handle it via 4.4. merge window. This pull request also contains two cleanups.
2015-10-29KVM: s390: use simple switch statement as multiplexerChristian Borntraeger1-21/+21
We currently do some magic shifting (by exploiting that exit codes are always a multiple of 4) and a table lookup to jump into the exit handlers. This causes some calculations and checks, just to do an potentially expensive function call. Changing that to a switch statement gives the compiler the chance to inline and dynamically decide between jump tables or inline compare and branches. In addition it makes the code more readable. bloat-o-meter gives me a small reduction in code size: add/remove: 0/7 grow/shrink: 1/1 up/down: 986/-1334 (-348) function old new delta kvm_handle_sie_intercept 72 1058 +986 handle_prog 704 696 -8 handle_noop 54 - -54 handle_partial_execution 60 - -60 intercept_funcs 120 - -120 handle_instruction 198 - -198 handle_validity 210 - -210 handle_stop 316 - -316 handle_external_interrupt 368 - -368 Right now my gcc does conditional branches instead of jump tables. The inlining seems to give us enough cycles as some micro-benchmarking shows minimal improvements, but still in noise. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2015-10-29KVM: s390: drop useless newline in debugging dataChristian Borntraeger1-4/+4
the s390 debug feature does not need newlines. In fact it will result in empty lines. Get rid of 4 leftovers. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2015-10-29KVM: s390: SCA must not cross page boundariesDavid Hildenbrand1-1/+3
We seemed to have missed a few corner cases in commit f6c137ff00a4 ("KVM: s390: randomize sca address"). The SCA has a maximum size of 2112 bytes. By setting the sca_offset to some unlucky numbers, we exceed the page. 0x7c0 (1984) -> Fits exactly 0x7d0 (2000) -> 16 bytes out 0x7e0 (2016) -> 32 bytes out 0x7f0 (2032) -> 48 bytes out One VCPU entry is 32 bytes long. For the last two cases, we actually write data to the other page. 1. The address of the VCPU. 2. Injection/delivery/clearing of SIGP externall calls via SIGP IF. Especially the 2. happens regularly. So this could produce two problems: 1. The guest losing/getting external calls. 2. Random memory overwrites in the host. So this problem happens on every 127 + 128 created VM with 64 VCPUs. Cc: stable@vger.kernel.org # v3.15+ Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2015-10-22KVM: arm: Do not indent the arguments of DECLARE_BITMAPMichal Marek1-4/+4
Besides being a coding style issue, it confuses make tags: ctags: Warning: include/kvm/arm_vgic.h:307: null expansion of name pattern "\1" ctags: Warning: include/kvm/arm_vgic.h:308: null expansion of name pattern "\1" ctags: Warning: include/kvm/arm_vgic.h:309: null expansion of name pattern "\1" ctags: Warning: include/kvm/arm_vgic.h:317: null expansion of name pattern "\1" Cc: kvmarm@lists.cs.columbia.edu Signed-off-by: Michal Marek <mmarek@suse.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm64: kvm: restore EL1N SP for panicMark Rutland1-0/+8
If we panic in hyp mode, we inject a call to panic() into the EL1N host kernel. If a guest context is active, we first attempt to restore the minimal amount of state necessary to execute the host kernel with restore_sysregs. However, the SP is restored as part of restore_common_regs, and so we may return to the host's panic() function with the SP of the guest. Any calculations based on the SP will be bogus, and any attempt to access the stack will result in recursive data aborts. When running Linux as a guest, the guest's EL1N SP is like to be some valid kernel address. In this case, the host kernel may use that region as a stack for panic(), corrupting it in the process. Avoid the problem by restoring the host SP prior to returning to the host. To prevent misleading backtraces in the host, the FP is zeroed at the same time. We don't need any of the other "common" registers in order to panic successfully. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: <kvmarm@lists.cs.columbia.edu> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Add tracepoints for vgic and timerChristoffer Dall3-0/+72
The VGIC and timer code for KVM arm/arm64 doesn't have any tracepoints or tracepoint infrastructure defined. Rewriting some of the timer code handling showed me how much we need this, so let's add these simple trace points once and for all and we can easily expand with additional trace points in these files as we go along. Cc: Wei Huang <wei@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Improve kvm_exit tracepointChristoffer Dall4-4/+44
The ARM architecture only saves the exit class to the HSR (ESR_EL2 for arm64) on synchronous exceptions, not on asynchronous exceptions like an IRQ. However, we only report the exception class on kvm_exit, which is confusing because an IRQ looks like it exited at some PC with the same reason as the previous exit. Add a lookup table for the exception index and prepend the kvm_exit tracepoint text with the exception type to clarify this situation. Also resolve the exception class (EC) to a human-friendly text version so the trace output becomes immediately usable for debugging this code. Cc: Wei Huang <wei@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: Fix vGIC documentationPavel Fedin1-8/+10
Correct some old mistakes in the API documentation: 1. VCPU is identified by index (using kvm_get_vcpu() function), but "cpu id" can be mistaken for affinity ID. 2. Some error codes are wrong. [ Slightly tweaked some grammer and did some s/CPU index/vcpu_index/ in the descriptions. -Christoffer ] Signed-off-by: Pavel Fedin <p.fedin@samsung.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: implement kvm_arm_[halt,resume]_guestEric Auger3-4/+37
We introduce kvm_arm_halt_guest and resume functions. They will be used for IRQ forward state change. Halt is synchronous and prevents the guest from being re-entered. We use the same mechanism put in place for PSCI former pause, now renamed power_off. A new flag is introduced in arch vcpu state, pause, only meant to be used by those functions. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: check power_off in critical section before VCPU runEric Auger1-1/+2
In case a vcpu off PSCI call is called just after we executed the vcpu_sleep check, we can enter the guest although power_off is set. Let's check the power_off state in the critical section, just before entering the guest. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reported-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: check power_off in kvm_arch_vcpu_runnableEric Auger1-1/+2
kvm_arch_vcpu_runnable now also checks whether the power_off flag is set. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: arm/arm64: rename pause into power_offEric Auger4-19/+19
The kvm_vcpu_arch pause field is renamed into power_off to prepare for the introduction of a new pause field. Also vcpu_pause is renamed into vcpu_sleep since we will sleep until both power_off and pause are false. Signed-off-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM : Enable vhost device selection under KVM config menuWei Huang2-0/+4
vhost drivers provide guest VMs with better I/O performance and lower CPU utilization. This patch allows users to select vhost devices under KVM configuration menu on ARM. This makes vhost support on arm/arm64 on a par with other architectures (e.g. x86, ppc). Signed-off-by: Wei Huang <wei@redhat.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Support edge-triggered forwarded interruptsChristoffer Dall1-18/+22
We mark edge-triggered interrupts with the HW bit set as queued to prevent the VGIC code from injecting LRs with both the Active and Pending bits set at the same time while also setting the HW bit, because the hardware does not support this. However, this means that we must also clear the queued flag when we sync back a LR where the state on the physical distributor went from active to inactive because the guest deactivated the interrupt. At this point we must also check if the interrupt is pending on the distributor, and tell the VGIC to queue it again if it is. Since these actions on the sync path are extremely close to those for level-triggered interrupts, rename process_level_irq to process_queued_irq, allowing it to cater for both cases. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Rework the arch timer to use level-triggered semanticsChristoffer Dall5-108/+91
The arch timer currently uses edge-triggered semantics in the sense that the line is never sampled by the vgic and lowering the line from the timer to the vgic doesn't have any effect on the pending state of virtual interrupts in the vgic. This means that we do not support a guest with the otherwise valid behavior of (1) disable interrupts (2) enable the timer (3) disable the timer (4) enable interrupts. Such a guest would validly not expect to see any interrupts on real hardware, but will see interrupts on KVM. This patch fixes this shortcoming through the following series of changes. First, we change the flow of the timer/vgic sync/flush operations. Now the timer is always flushed/synced before the vgic, because the vgic samples the state of the timer output. This has the implication that we move the timer operations in to non-preempible sections, but that is fine after the previous commit getting rid of hrtimer schedules on every entry/exit. Second, we change the internal behavior of the timer, letting the timer keep track of its previous output state, and only lower/raise the line to the vgic when the state changes. Note that in theory this could have been accomplished more simply by signalling the vgic every time the state *potentially* changed, but we don't want to be hitting the vgic more often than necessary. Third, we get rid of the use of the map->active field in the vgic and instead simply set the interrupt as active on the physical distributor whenever the input to the GIC is asserted and conversely clear the physical active state when the input to the GIC is deasserted. Fourth, and finally, we now initialize the timer PPIs (and all the other unused PPIs for now), to be level-triggered, and modify the sync code to sample the line state on HW sync and re-inject a new interrupt if it is still pending at that time. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Add forwarded physical interrupts documentationChristoffer Dall1-0/+187
Forwarded physical interrupts on arm/arm64 is a tricky concept and the way we deal with them is not apparently easy to understand by reading various specs. Therefore, add a proper documentation file explaining the flow and rationale of the behavior of the vgic. Some of this text was contributed by Marc Zyngier and edited by me. Omissions and errors are all mine. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Use appropriate define in VGIC reset codeChristoffer Dall1-2/+6
We currently initialize the SGIs to be enabled in the VGIC code, but we use the VGIC_NR_PPIS define for this purpose, instead of the the more natural VGIC_NR_SGIS. Change this slightly confusing use of the defines. Note: This should have no functional change, as both names are defined to the number 16. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: Implement GICD_ICFGR as RO for PPIsChristoffer Dall1-3/+2
The GICD_ICFGR allows the bits for the SGIs and PPIs to be read only. We currently simulate this behavior by writing a hardcoded value to the register for the SGIs and PPIs on every write of these bits to the register (ignoring what the guest actually wrote), and by writing the same value as the reset value to the register. This is a bit counter-intuitive, as the register is RO for these bits, and we can just implement it that way, allowing us to control the value of the bits purely in the reset code. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: vgic: Factor out level irq processing on guest exitChristoffer Dall1-38/+56
Currently vgic_process_maintenance() processes dealing with a completed level-triggered interrupt directly, but we are soon going to reuse this logic for level-triggered mapped interrupts with the HW bit set, so move this logic into a separate static function. Probably the most scary part of this commit is convincing yourself that the current flow is safe compared to the old one. In the following I try to list the changes and why they are harmless: Move vgic_irq_clear_queued after kvm_notify_acked_irq: Harmless because the only potential effect of clearing the queued flag wrt. kvm_set_irq is that vgic_update_irq_pending does not set the pending bit on the emulated CPU interface or in the pending_on_cpu bitmask if the function is called with level=1. However, the point of kvm_notify_acked_irq is to call kvm_set_irq with level=0, and we set the queued flag again in __kvm_vgic_sync_hwstate later on if the level is stil high. Move vgic_set_lr before kvm_notify_acked_irq: Also, harmless because the LR are cpu-local operations and kvm_notify_acked only affects the dist Move vgic_dist_irq_clear_soft_pend after kvm_notify_acked_irq: Also harmless, because now we check the level state in the clear_soft_pend function and lower the pending bits if the level is low. Reviewed-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22arm/arm64: KVM: arch_timer: Only schedule soft timer on vcpu_blockChristoffer Dall5-40/+72
We currently schedule a soft timer every time we exit the guest if the timer did not expire while running the guest. This is really not necessary, because the only work we do in the timer work function is to kick the vcpu. Kicking the vcpu does two things: (1) If the vpcu thread is on a waitqueue, make it runnable and remove it from the waitqueue. (2) If the vcpu is running on a different physical CPU from the one doing the kick, it sends a reschedule IPI. The second case cannot happen, because the soft timer is only ever scheduled when the vcpu is not running. The first case is only relevant when the vcpu thread is on a waitqueue, which is only the case when the vcpu thread has called kvm_vcpu_block(). Therefore, we only need to make sure a timer is scheduled for kvm_vcpu_block(), which we do by encapsulating all calls to kvm_vcpu_block() with kvm_timer_{un}schedule calls. Additionally, we only schedule a soft timer if the timer is enabled and unmasked, since it is useless otherwise. Note that theoretically userspace can use the SET_ONE_REG interface to change registers that should cause the timer to fire, even if the vcpu is blocked without a scheduled timer, but this case was not supported before this patch and we leave it for future work for now. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-22KVM: Add kvm_arch_vcpu_{un}blocking callbacksChristoffer Dall8-0/+20
Some times it is useful for architecture implementations of KVM to know when the VCPU thread is about to block or when it comes back from blocking (arm/arm64 needs to know this to properly implement timers, for example). Therefore provide a generic architecture callback function in line with what we do elsewhere for KVM generic-arch interactions. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2015-10-21KVM: PPC: Book3S HV: Handle H_DOORBELL on the guest exit pathGautham R. Shenoy1-3/+14
Currently a CPU running a guest can receive a H_DOORBELL in the following two cases: 1) When the CPU is napping due to CEDE or there not being a guest vcpu. 2) The CPU is running the guest vcpu. Case 1), the doorbell message is not cleared since we were waking up from nap. Hence when the EE bit gets set on transition from guest to host, the H_DOORBELL interrupt is delivered to the host and the corresponding handler is invoked. However in Case 2), the message gets cleared by the action of taking the H_DOORBELL interrupt. Since the CPU was running a guest, instead of invoking the doorbell handler, the code invokes the second-level interrupt handler to switch the context from the guest to the host. At this point the setting of the EE bit doesn't result in the CPU getting the doorbell interrupt since it has already been delivered once. So, the handler for this doorbell is never invoked! This causes softlockups if the missed DOORBELL was an IPI sent from a sibling subcore on the same CPU. This patch fixes it by explitly invoking the doorbell handler on the exit path if the exit reason is H_DOORBELL similar to the way an EXTERNAL interrupt is handled. Since this will also handle Case 1), we can unconditionally clear the doorbell message in kvmppc_check_wake_reason. Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2015-10-21KVM: PPC: Implement extension to report number of memslotsNikunj A Dadhania1-0/+3
QEMU assumes 32 memslots if this extension is not implemented. Although, current value of KVM_USER_MEM_SLOTS is 32, once KVM_USER_MEM_SLOTS changes QEMU would take a wrong value. Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2015-10-21KVM: PPC: Book3S HV: Make H_REMOVE return correct HPTE value for absent HPTEsPaul Mackerras1-0/+2
This fixes a bug where the old HPTE value returned by H_REMOVE has the valid bit clear if the HPTE was an absent HPTE, as happens for HPTEs for emulated MMIO pages and for RAM pages that have been paged out by the host. If the absent bit is set, we clear it and set the valid bit, because from the guest's point of view, the HPTE is valid. Signed-off-by: Paul Mackerras <paulus@samba.org>
2015-10-21KVM: PPC: Book3S HV: Don't fall back to smaller HPT size in allocation ioctlPaul Mackerras1-1/+2
Currently the KVM_PPC_ALLOCATE_HTAB will try to allocate the requested size of HPT, and if that is not possible, then try to allocate smaller sizes (by factors of 2) until either a minimum is reached or the allocation succeeds. This is not ideal for userspace, particularly in migration scenarios, where the destination VM really does require the size requested. Also, the minimum HPT size of 256kB may be insufficient for the guest to run successfully. This removes the fallback to smaller sizes on allocation failure for the KVM_PPC_ALLOCATE_HTAB ioctl. The fallback still exists for the case where the HPT is allocated at the time the first VCPU is run, if no HPT has been allocated by ioctl by that time. Signed-off-by: Paul Mackerras <paulus@samba.org>
2015-10-20arm/arm64: KVM: Fix disabled distributor operationChristoffer Dall1-5/+6
We currently do a single update of the vgic state when the distributor enable/disable control register is accessed and then bypass updating the state for as long as the distributor remains disabled. This is incorrect, because updating the state does not consider the distributor enable bit, and this you can end up in a situation where an interrupt is marked as pending on the CPU interface, but not pending on the distributor, which is an impossible state to be in, and triggers a warning. Consider for example the following sequence of events: 1. An interrupt is marked as pending on the distributor - the interrupt is also forwarded to the CPU interface 2. The guest turns off the distributor (it's about to do a reboot) - we stop updating the CPU interface state from now on 3. The guest disables the pending interrupt - we remove the pending state from the distributor, but don't touch the CPU interface, see point 2. Since the distributor disable bit really means that no interrupts should be forwarded to the CPU interface, we modify the code to keep updating the internal VGIC state, but always set the CPU interface pending bits to zero when the distributor is disabled. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>