- 25 Feb, 2022 8 commits
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Li RongQing authored
When sending a call-function IPI-many to vCPUs, yield to the IPI target vCPU which is marked as preempted. but when emulating HLT, an idling vCPU will be voluntarily scheduled out and mark as preempted from the guest kernel perspective. yielding to idle vCPU is pointless and increase unnecessary vmexit, maybe miss the true preempted vCPU so yield to IPI target vCPU only if vCPU is busy and preempted Signed-off-by:
Li RongQing <lirongqing@baidu.com> Message-Id: <1644380201-29423-1-git-send-email-lirongqing@baidu.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com>
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Dexuan Cui authored
When Linux runs as an Isolated VM on Hyper-V, it supports AMD SEV-SNP but it's partially enlightened, i.e. cc_platform_has( CC_ATTR_GUEST_MEM_ENCRYPT) is true but sev_active() is false. Commit 4d96f910 per se is good, but with it now kvm_setup_vsyscall_timeinfo() -> kvmclock_init_mem() calls set_memory_decrypted(), and later gets stuck when trying to zere out the pages pointed by 'hvclock_mem', if Linux runs as an Isolated VM on Hyper-V. The cause is that here now the Linux VM should no longer access the original guest physical addrss (GPA); instead the VM should do memremap() and access the original GPA + ms_hyperv.shared_gpa_boundary: see the example code in drivers/hv/connection.c: vmbus_connect() or drivers/hv/ring_buffer.c: hv_ringbuffer_init(). If the VM tries to access the original GPA, it keepts getting injected a fault by Hyper-V and gets stuck there. Here the issue happens only when the VM has >=65 vCPUs, because the global static array hv_clock_boot[] can hold 64 "struct pvclock_vsyscall_time_info" (the sizeof of the struct is 64 bytes), so kvmclock_init_mem() only allocates memory in the case of vCPUs > 64. Since the 'hvclock_mem' pages are only useful when the kvm clock is supported by the underlying hypervisor, fix the issue by returning early when Linux VM runs on Hyper-V, which doesn't support kvm clock. Fixes: 4d96f910 ("x86/sev: Replace occurrences of sev_active() with cc_platform_has()") Tested-by:
Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by:
Dexuan Cui <decui@microsoft.com> Message-Id: <20220225084600.17817-1-decui@microsoft.com> Signed-off-by:
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Wanpeng Li authored
Even if "no-kvmclock" is passed in cmdline parameter, the guest kernel still allocates hvclock_mem which is scaled by the number of vCPUs, let's check kvmclock enable in advance to avoid this memory waste. Signed-off-by:
Wanpeng Li <wanpengli@tencent.com> Message-Id: <1645520523-30814-1-git-send-email-wanpengli@tencent.com> Signed-off-by:
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Wanpeng Li authored
MWAIT is advertised in host is not overcommitted scenario, however, PV TLB/sched yield should be enabled in host overcommitted scenario. Let's add the MWAIT checking when enabling PV TLB/sched yield. Signed-off-by:
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Paolo Bonzini authored
Merge tag 'kvmarm-fixes-5.17-4' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.17, take #4 - Correctly synchronise PMR and co on PSCI CPU_SUSPEND - Skip tests that depend on GICv3 when the HW isn't available
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Mark Brown authored
The arch_timer and vgic_irq kselftests assume that they can create a vgic-v3, using the library function vgic_v3_setup() which aborts with a test failure if it is not possible to do so. Since vgic-v3 can only be instantiated on systems where the host has GICv3 this leads to false positives on older systems where that is not the case. Fix this by changing vgic_v3_setup() to return an error if the vgic can't be instantiated and have the callers skip if this happens. We could also exit flagging a skip in vgic_v3_setup() but this would prevent future test cases conditionally deciding which GIC to use or generally doing more complex output. Signed-off-by:
Mark Brown <broonie@kernel.org> Reviewed-by:
Andrew Jones <drjones@redhat.com> Tested-by:
Ricardo Koller <ricarkol@google.com> Signed-off-by:
Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220223131624.1830351-1-broonie@kernel.org
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Sean Christopherson authored
Revert back to refreshing vmcs.HOST_CR3 immediately prior to VM-Enter. The PCID (ASID) part of CR3 can be bumped without KVM being scheduled out, as the kernel will switch CR3 during __text_poke(), e.g. in response to a static key toggling. If switch_mm_irqs_off() chooses a new ASID for the mm associate with KVM, KVM will do VM-Enter => VM-Exit with a stale vmcs.HOST_CR3. Add a comment to explain why KVM must wait until VM-Enter is imminent to refresh vmcs.HOST_CR3. The following splat was captured by stashing vmcs.HOST_CR3 in kvm_vcpu and adding a WARN in load_new_mm_cr3() to fire if a new ASID is being loaded for the KVM-associated mm while KVM has a "running" vCPU: static void load_new_mm_cr3(pgd_t *pgdir, u16 new_asid, bool need_flush) { struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); ... WARN(vcpu && (vcpu->cr3 & GENMASK(11, 0)) != (new_mm_cr3 & GENMASK(11, 0)) && (vcpu->cr3 & PHYSICAL_PAGE_MASK) == (new_mm_cr3 & PHYSICAL_PAGE_MASK), "KVM is hosed, loading CR3 = %lx, vmcs.HOST_CR3 = %lx", new_mm_cr3, vcpu->cr3); } ------------[ cut here ]------------ KVM is hosed, loading CR3 = 8000000105393004, vmcs.HOST_CR3 = 105393003 WARNING: CPU: 4 PID: 20717 at arch/x86/mm/tlb.c:291 load_new_mm_cr3+0x82/0xe0 Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel CPU: 4 PID: 20717 Comm: stable Tainted: G W 5.17.0-rc3+ #747 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:load_new_mm_cr3+0x82/0xe0 RSP: 0018:ffffc9000489fa98 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 8000000105393004 RCX: 0000000000000027 RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff888277d1b788 RBP: 0000000000000004 R08: ffff888277d1b780 R09: ffffc9000489f8b8 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: ffff88810678a800 R14: 0000000000000004 R15: 0000000000000c33 FS: 00007fa9f0e72700(0000) GS:ffff888277d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000001001b5003 CR4: 0000000000172ea0 Call Trace: <TASK> switch_mm_irqs_off+0x1cb/0x460 __text_poke+0x308/0x3e0 text_poke_bp_batch+0x168/0x220 text_poke_finish+0x1b/0x30 arch_jump_label_transform_apply+0x18/0x30 static_key_slow_inc_cpuslocked+0x7c/0x90 static_key_slow_inc+0x16/0x20 kvm_lapic_set_base+0x116/0x190 kvm_set_apic_base+0xa5/0xe0 kvm_set_msr_common+0x2f4/0xf60 vmx_set_msr+0x355/0xe70 [kvm_intel] kvm_set_msr_ignored_check+0x91/0x230 kvm_emulate_wrmsr+0x36/0x120 vmx_handle_exit+0x609/0x6c0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x146f/0x1b80 kvm_vcpu_ioctl+0x279/0x690 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae </TASK> ---[ end trace 0000000000000000 ]--- This reverts commit 15ad9762. Fixes: 15ad9762 ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()") Reported-by:Wanpeng Li <kernellwp@gmail.com> Cc: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by:
Sean Christopherson <seanjc@google.com> Acked-by:
Lai Jiangshan <jiangshanlai@gmail.com> Message-Id: <20220224191917.3508476-3-seanjc@google.com> Signed-off-by:
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Sean Christopherson authored
Undo a nested VMX fix as a step toward reverting the commit it fixed, 15ad9762 ("KVM: VMX: Save HOST_CR3 in vmx_prepare_switch_to_guest()"), as the underlying premise that "host CR3 in the vcpu thread can only be changed when scheduling" is wrong. This reverts commit a9f2705e. Signed-off-by:
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- 24 Feb, 2022 2 commits
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Maxim Levitsky authored
KVM: x86: nSVM: disallow userspace setting of MSR_AMD64_TSC_RATIO to non default value when tsc scaling disabled If nested tsc scaling is disabled, MSR_AMD64_TSC_RATIO should never have non default value. Due to way nested tsc scaling support was implmented in qemu, it would set this msr to 0 when nested tsc scaling was disabled. Ignore that value for now, as it causes no harm. Fixes: 5228eb96 ("KVM: x86: nSVM: implement nested TSC scaling") Cc: stable@vger.kernel.org Signed-off-by:
Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220223115649.319134-1-mlevitsk@redhat.com> Signed-off-by:
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Liang Zhang authored
In current async pagefault logic, when a page is ready, KVM relies on kvm_arch_can_dequeue_async_page_present() to determine whether to deliver a READY event to the Guest. This function test token value of struct kvm_vcpu_pv_apf_data, which must be reset to zero by Guest kernel when a READY event is finished by Guest. If value is zero meaning that a READY event is done, so the KVM can deliver another. But the kvm_arch_setup_async_pf() may produce a valid token with zero value, which is confused with previous mention and may lead the loss of this READY event. This bug may cause task blocked forever in Guest: INFO: task stress:7532 blocked for more than 1254 seconds. Not tainted 5.10.0 #16 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:stress state:D stack: 0 pid: 7532 ppid: 1409 flags:0x00000080 Call Trace: __schedule+0x1e7/0x650 schedule+0x46/0xb0 kvm_async_pf_task_wait_schedule+0xad/0xe0 ? exit_to_user_mode_prepare+0x60/0x70 __kvm_handle_async_pf+0x4f/0xb0 ? asm_exc_page_fault+0x8/0x30 exc_page_fault+0x6f/0x110 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x402d00 RSP: 002b:00007ffd31912500 EFLAGS: 00010206 RAX: 0000000000071000 RBX: ffffffffffffffff RCX: 00000000021a32b0 RDX: 000000000007d011 RSI: 000000000007d000 RDI: 00000000021262b0 RBP: 00000000021262b0 R08: 0000000000000003 R09: 0000000000000086 R10: 00000000000000eb R11: 00007fefbdf2baa0 R12: 0000000000000000 R13: 0000000000000002 R14: 000000000007d000 R15: 0000000000001000 Signed-off-by:Liang Zhang <zhangliang5@huawei.com> Message-Id: <20220222031239.1076682-1-zhangliang5@huawei.com> Cc: stable@vger.kernel.org Signed-off-by:
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- 22 Feb, 2022 2 commits
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Paolo Bonzini authored
By request of Nick Piggin: > Patch 3 requires a KVM_CAP_PPC number allocated. QEMU maintainers are > happy with it (link in changelog) just waiting on KVM upstreaming. Do > you have objections to the series going to ppc/kvm tree first, or > another option is you could take patch 3 alone first (it's relatively > independent of the other 2) and ppc/kvm gets it from you?
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Nicholas Piggin authored
Add KVM_CAP_PPC_AIL_MODE_3 to advertise the capability to set the AIL resource mode to 3 with the H_SET_MODE hypercall. This capability differs between processor types and KVM types (PR, HV, Nested HV), and affects guest-visible behaviour. QEMU will implement a cap-ail-mode-3 to control this behaviour[1], and use the KVM CAP if available to determine KVM support[2]. Reviewed-by:
Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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- 18 Feb, 2022 2 commits
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Wanpeng Li authored
Inspired by commit 3553ae56 (x86/kvm: Don't use pvqspinlock code if only 1 vCPU), on a VM with only 1 vCPU, there is no need to enable pv tlb/ipi/sched_yield and we can save the memory for __pv_cpu_mask. Signed-off-by:
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Leonardo Bras authored
On non-x86_64 builds, helpers gtod_is_based_on_tsc() and kvm_guest_supported_xfd() are defined but never used. Because these are static inline but are in a .c file, some compilers do warn for them with -Wunused-function, which becomes an error if -Werror is present. Add #ifdef so they are only defined in x86_64 builds. Reported-by:
kernel test robot <lkp@intel.com> Signed-off-by:
Leonardo Bras <leobras@redhat.com> Message-Id: <20220218034100.115702-1-leobras@redhat.com> Signed-off-by:
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- 17 Feb, 2022 6 commits
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Leonardo Bras authored
kvm_vcpu_arch currently contains the guest supported features in both guest_supported_xcr0 and guest_fpu.fpstate->user_xfeatures field. Currently both fields are set to the same value in kvm_vcpu_after_set_cpuid() and are not changed anywhere else after that. Since it's not good to keep duplicated data, remove guest_supported_xcr0. To keep the code more readable, introduce kvm_guest_supported_xcr() and kvm_guest_supported_xfd() to replace the previous usages of guest_supported_xcr0. Signed-off-by:
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Leonardo Bras authored
During host/guest switch (like in kvm_arch_vcpu_ioctl_run()), the kernel swaps the fpu between host/guest contexts, by using fpu_swap_kvm_fpstate(). When xsave feature is available, the fpu swap is done by: - xsave(s) instruction, with guest's fpstate->xfeatures as mask, is used to store the current state of the fpu registers to a buffer. - xrstor(s) instruction, with (fpu_kernel_cfg.max_features & XFEATURE_MASK_FPSTATE) as mask, is used to put the buffer into fpu regs. For xsave(s) the mask is used to limit what parts of the fpu regs will be copied to the buffer. Likewise on xrstor(s), the mask is used to limit what parts of the fpu regs will be changed. The mask for xsave(s), the guest's fpstate->xfeatures, is defined on kvm_arch_vcpu_create(), which (in summary) sets it to all features supported by the cpu which are enabled on kernel config. This means that xsave(s) will save to guest buffer all the fpu regs contents the cpu has enabled when the guest is paused, even if they are not used. This would not be an issue, if xrstor(s) would also do that. xrstor(s)'s mask for host/guest swap is basically every valid feature contained in kernel config, except XFEATURE_MASK_PKRU. Accordingto kernel src, it is instead switched in switch_to() and flush_thread(). Then, the following happens with a host supporting PKRU starts a guest that does not support it: 1 - Host has XFEATURE_MASK_PKRU set. 1st switch to guest, 2 - xsave(s) fpu regs to host fpustate (buffer has XFEATURE_MASK_PKRU) 3 - xrstor(s) guest fpustate to fpu regs (fpu regs have XFEATURE_MASK_PKRU) 4 - guest runs, then switch back to host, 5 - xsave(s) fpu regs to guest fpstate (buffer now have XFEATURE_MASK_PKRU) 6 - xrstor(s) host fpstate to fpu regs. 7 - kvm_vcpu_ioctl_x86_get_xsave() copy guest fpstate to userspace (with XFEATURE_MASK_PKRU, which should not be supported by guest vcpu) On 5, even though the guest does not support PKRU, it does have the flag set on guest fpstate, which is transferred to userspace via vcpu ioctl KVM_GET_XSAVE. This becomes a problem when the user decides on migrating the above guest to another machine that does not support PKRU: the new host restores guest's fpu regs to as they were before (xrstor(s)), but since the new host don't support PKRU, a general-protection exception ocurs in xrstor(s) and that crashes the guest. This can be solved by making the guest's fpstate->user_xfeatures hold a copy of guest_supported_xcr0. This way, on 7 the only flags copied to userspace will be the ones compatible to guest requirements, and thus there will be no issue during migration. As a bonus, it will also fail if userspace tries to set fpu features (with the KVM_SET_XSAVE ioctl) that are not compatible to the guest configuration. Such features will never be returned by KVM_GET_XSAVE or KVM_GET_XSAVE2. Also, since kvm_vcpu_after_set_cpuid() now sets fpstate->user_xfeatures, there is not need to set it in kvm_check_cpuid(). So, change fpstate_realloc() so it does not touch fpstate->user_xfeatures if a non-NULL guest_fpu is passed, which is the case when kvm_check_cpuid() calls it. Signed-off-by: -
Anton Romanov authored
If vcpu has tsc_always_catchup set each request updates pvclock data. KVM_HC_CLOCK_PAIRING consumers such as ptp_kvm_x86 rely on tsc read on host's side and do hypercall inside pvclock_read_retry loop leading to infinite loop in such situation. v3: Removed warn Changed return code to KVM_EFAULT v2: Added warn Signed-off-by:Anton Romanov <romanton@google.com> Message-Id: <20220216182653.506850-1-romanton@google.com> Signed-off-by:
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Wanpeng Li authored
I saw the below splatting after the host suspended and resumed. WARNING: CPU: 0 PID: 2943 at kvm/arch/x86/kvm/../../../virt/kvm/kvm_main.c:5531 kvm_resume+0x2c/0x30 [kvm] CPU: 0 PID: 2943 Comm: step_after_susp Tainted: G W IOE 5.17.0-rc3+ #4 RIP: 0010:kvm_resume+0x2c/0x30 [kvm] Call Trace: <TASK> syscore_resume+0x90/0x340 suspend_devices_and_enter+0xaee/0xe90 pm_suspend.cold+0x36b/0x3c2 state_store+0x82/0xf0 kernfs_fop_write_iter+0x1b6/0x260 new_sync_write+0x258/0x370 vfs_write+0x33f/0x510 ksys_write+0xc9/0x160 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae lockdep_is_held() can return -1 when lockdep is disabled which triggers this warning. Let's use lockdep_assert_not_held() which can detect incorrect calls while holding a lock and it also avoids false negatives when lockdep is disabled. Signed-off-by: -
Aaron Lewis authored
Follow the precedent set by other architectures that support the VCPU ioctl, KVM_ENABLE_CAP, and advertise the VM extension, KVM_CAP_ENABLE_CAP. This way, userspace can ensure that KVM_ENABLE_CAP is available on a vcpu before using it. Fixes: 5c919412 ("kvm/x86: Hyper-V synthetic interrupt controller") Signed-off-by:
Aaron Lewis <aaronlewis@google.com> Message-Id: <20220214212950.1776943-1-aaronlewis@google.com> Cc: stable@vger.kernel.org Signed-off-by:
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Oliver Upton authored
In order to properly emulate the WFI instruction, KVM reads back ICH_VMCR_EL2 and enables doorbells for GICv4. These preparations are necessary in order to recognize pending interrupts in kvm_arch_vcpu_runnable() and return to the guest. Until recently, this work was done by kvm_arch_vcpu_{blocking,unblocking}(). Since commit 6109c5a6 ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook"), these callbacks were gutted and superseded by kvm_vcpu_wfi(). It is important to note that KVM implements PSCI CPU_SUSPEND calls as a WFI within the guest. However, the implementation calls directly into kvm_vcpu_halt(), which skips the needed work done in kvm_vcpu_wfi() to detect pending interrupts. Fix the issue by calling the WFI helper. Fixes: 6109c5a6 ("KVM: arm64: Move vGIC v4 handling for WFI out arch callback hook") Signed-off-by:Oliver Upton <oupton@google.com> Signed-off-by:
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- 14 Feb, 2022 2 commits
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Jim Mattson authored
AMD's event select is 3 nybbles, with the high nybble in bits 35:32 of a PerfEvtSeln MSR. Don't mask off the high nybble when configuring a RAW perf event. Fixes: ca724305 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Signed-off-by:
Jim Mattson <jmattson@google.com> Message-Id: <20220203014813.2130559-2-jmattson@google.com> Reviewed-by:
David Dunn <daviddunn@google.com> Signed-off-by:
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Jim Mattson authored
AMD's event select is 3 nybbles, with the high nybble in bits 35:32 of a PerfEvtSeln MSR. Don't drop the high nybble when setting up the config field of a perf_event_attr structure for a call to perf_event_create_kernel_counter(). Fixes: ca724305 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") Reported-by:
Stephane Eranian <eranian@google.com> Signed-off-by:
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- 11 Feb, 2022 6 commits
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Maxim Levitsky authored
If svm_deliver_avic_intr is called just after the target vcpu's AVIC got inhibited, it might read a stale value of vcpu->arch.apicv_active which can lead to the target vCPU not noticing the interrupt. To fix this use load-acquire/store-release so that, if the target vCPU is IN_GUEST_MODE, we're guaranteed to see a previous disabling of the AVIC. If AVIC has been disabled in the meanwhile, proceed with the KVM_REQ_EVENT-based delivery. Incomplete IPI vmexit has the same races as svm_deliver_avic_intr, and in fact it can be handled in exactly the same way; the only difference lies in who has set IRR, whether svm_deliver_interrupt or the processor. Therefore, svm_complete_interrupt_delivery can be used to fix incomplete IPI vmexits as well. Co-developed-by:
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Paolo Bonzini authored
SVM has to set IRR for both the AVIC and the software-LAPIC case, so pull it up to the common function that handles both configurations. Signed-off-by: -
Maxim Levitsky authored
The check on the current CPU adds an extra level of indentation to svm_deliver_avic_intr and conflates documentation on what happens if the vCPU exits (of interest to svm_deliver_avic_intr) and migrates (only of interest to avic_ring_doorbell, which calls get/put_cpu()). Extract the wrmsr to a separate function and rewrite the comment in svm_deliver_avic_intr(). Co-developed-by:
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Muhammad Usama Anjum authored
There is no vmx_pi_mmio_test file. Remove it to get rid of error while creation of selftest archive: rsync: [sender] link_stat "/kselftest/kvm/x86_64/vmx_pi_mmio_test" failed: No such file or directory (2) rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1333) [sender=3.2.3] Fixes: 6a581508 ("selftest: KVM: Add intra host migration tests") Reported-by:
"kernelci.org bot" <bot@kernelci.org> Signed-off-by:
Muhammad Usama Anjum <usama.anjum@collabora.com> Message-Id: <20220210172352.1317554-1-usama.anjum@collabora.com> Signed-off-by:
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Paolo Bonzini authored
Merge tag 'kvmarm-fixes-5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD KVM/arm64 fixes for 5.17, take #3 - Fix pending state read of a HW interrupt
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Marc Zyngier authored
It appears that a read access to GIC[DR]_I[CS]PENDRn doesn't always result in the pending interrupts being accurately reported if they are mapped to a HW interrupt. This is particularily visible when acking the timer interrupt and reading the GICR_ISPENDR1 register immediately after, for example (the interrupt appears as not-pending while it really is...). This is because a HW interrupt has its 'active and pending state' kept in the *physical* distributor, and not in the virtual one, as mandated by the spec (this is what allows the direct deactivation). The virtual distributor only caries the pending and active *states* (note the plural, as these are two independent and non-overlapping states). Fix it by reading the HW state back, either from the timer itself or from the distributor if necessary. Reported-by:
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- 10 Feb, 2022 1 commit
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David Woodhouse authored
There are circumstances whem kvm_xen_update_runstate_guest() should not sleep because it ends up being called from __schedule() when the vCPU is preempted: [ 222.830825] kvm_xen_update_runstate_guest+0x24/0x100 [ 222.830878] kvm_arch_vcpu_put+0x14c/0x200 [ 222.830920] kvm_sched_out+0x30/0x40 [ 222.830960] __schedule+0x55c/0x9f0 To handle this, make it use the same trick as __kvm_xen_has_interrupt(), of using the hva from the gfn_to_hva_cache directly. Then it can use pagefault_disable() around the accesses and just bail out if the page is absent (which is unlikely). I almost switched to using a gfn_to_pfn_cache here and bailing out if kvm_map_gfn() fails, like kvm_steal_time_set_preempted() does — but on closer inspection it looks like kvm_map_gfn() will *always* fail in atomic context for a page in IOMEM, which means it will silently fail to make the update every single time for such guests, AFAICT. So I didn't do it that way after all. And will probably fix that one too. Cc: stable@vger.kernel.org Fixes: 30b5c851 ("KVM: x86/xen: Add support for vCPU runstate information") Signed-off-by:
David Woodhouse <dwmw@amazon.co.uk> Message-Id: <b17a93e5ff4561e57b1238e3e7ccd0b613eb827e.camel@infradead.org> Signed-off-by:
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- 08 Feb, 2022 9 commits
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Maxim Levitsky authored
asm/svm.h is the correct place for all values that are defined in the SVM spec, and that includes AVIC. Also add some values from the spec that were not defined before and will be soon useful. Signed-off-by:
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Maxim Levitsky authored
kvm_apic_update_apicv is called when AVIC is still active, thus IRR bits can be set by the CPU after it is called, and don't cause the irr_pending to be set to true. Also logic in avic_kick_target_vcpu doesn't expect a race with this function so to make it simple, just keep irr_pending set to true and let the next interrupt injection to the guest clear it. Signed-off-by:
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Maxim Levitsky authored
Fix a corner case in which the L1 hypervisor intercepts interrupts (INTERCEPT_INTR) and either doesn't set virtual interrupt masking (V_INTR_MASKING) or enters a nested guest with EFLAGS.IF disabled prior to the entry. In this case, despite the fact that L1 intercepts the interrupts, KVM still needs to set up an interrupt window to wait before injecting the INTR vmexit. Currently the KVM instead enters an endless loop of 'req_immediate_exit'. Exactly the same issue also happens for SMIs and NMI. Fix this as well. Note that on VMX, this case is impossible as there is only 'vmexit on external interrupts' execution control which either set, in which case both host and guest's EFLAGS.IF are ignored, or not set, in which case no VMexits are delivered. Signed-off-by:
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Maxim Levitsky authored
KVM already honours few clean bits thus it makes sense to let the nested guest know about it. Note that KVM also doesn't check if the hardware supports clean bits, and therefore nested KVM was already setting clean bits and L0 KVM was already honouring them. Signed-off-by:
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Maxim Levitsky authored
While RSM induced VM entries are not full VM entries, they still need to be followed by actual VM entry to complete it, unlike setting the nested state. This patch fixes boot of hyperv and SMM enabled windows VM running nested on KVM, which fail due to this issue combined with lack of dirty bit setting. Signed-off-by:
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Maxim Levitsky authored
While usually, restoring the smm state makes the KVM enter the nested guest thus a different vmcb (vmcb02 vs vmcb01), KVM should still mark it as dirty, since hardware can in theory cache multiple vmcbs. Failure to do so, combined with lack of setting the nested_run_pending (which is fixed in the next patch), might make KVM re-enter vmcb01, which was just exited from, with completely different set of guest state registers (SMM vs non SMM) and without proper dirty bits set, which results in the CPU reusing stale IDTR pointer which leads to a guest shutdown on any interrupt. On the real hardware this usually doesn't happen, but when running nested, L0's KVM does check and honour few dirty bits, causing this issue to happen. This patch fixes boot of hyperv and SMM enabled windows VM running nested on KVM. Signed-off-by:
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Maxim Levitsky authored
Turns out that due to review feedback and/or rebases I accidentally moved the call to nested_svm_load_cr3 to be too early, before the NPT is enabled, which is very wrong to do. KVM can't even access guest memory at that point as nested NPT is needed for that, and of course it won't initialize the walk_mmu, which is main issue the patch was addressing. Fix this for real. Fixes: 232f75d3 ("KVM: nSVM: call nested_svm_load_cr3 on nested state load") Cc: stable@vger.kernel.org Signed-off-by:
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Maxim Levitsky authored
When the guest doesn't enable paging, and NPT/EPT is disabled, we use guest't paging CR3's as KVM's shadow paging pointer and we are technically in direct mode as if we were to use NPT/EPT. In direct mode we create SPTEs with user mode permissions because usually in the direct mode the NPT/EPT doesn't need to restrict access based on guest CPL (there are MBE/GMET extenstions for that but KVM doesn't use them). In this special "use guest paging as direct" mode however, and if CR4.SMAP/CR4.SMEP are enabled, that will make the CPU fault on each access and KVM will enter endless loop of page faults. Since page protection doesn't have any meaning in !PG case, just don't passthrough these bits. The fix is the same as was done for VMX in commit: commit 656ec4a4 ("KVM: VMX: fix SMEP and SMAP without EPT") This fixes the boot of windows 10 without NPT for good. (Without this patch, BSP boots, but APs were stuck in endless loop of page faults, causing the VM boot with 1 CPU) Signed-off-by:
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Sean Christopherson authored
Remove a WARN on an "AVIC IPI invalid target" exit, the WARN is trivial to trigger from guest as it will fail on any destination APIC ID that doesn't exist from the guest's perspective. Don't bother recording anything in the kernel log, the common tracepoint for kvm_avic_incomplete_ipi() is sufficient for debugging. This reverts commit 37ef0c44. Cc: stable@vger.kernel.org Signed-off-by:
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- 06 Feb, 2022 2 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4Linus Torvalds authored
Pull ext4 fixes from Ted Ts'o: "Various bug fixes for ext4 fast commit and inline data handling. Also fix regression introduced as part of moving to the new mount API" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: fs/ext4: fix comments mentioning i_mutex ext4: fix incorrect type issue during replay_del_range jbd2: fix kernel-doc descriptions for jbd2_journal_shrink_{scan,count}() ext4: fix potential NULL pointer dereference in ext4_fill_super() jbd2: refactor wait logic for transaction updates into a common function jbd2: cleanup unused functions declarations from jbd2.h ext4: fix error handling in ext4_fc_record_modified_inode() ext4: remove redundant max inline_size check in ext4_da_write_inline_data_begin() ext4: fix error handling in ext4_restore_inline_data() ext4: fast commit may miss file actions ext4: fast commit may not fallback for ineligible commit ext4: modify the logic of ext4_mb_new_blocks_simple ext4: prevent used blocks from being allocated during fast commit replay
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