diff options
| author | Like Xu <likexu@tencent.com> | 2022-09-23 00:13:55 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-11-09 12:31:36 -0500 |
| commit | de0f619564f4713bd548b82d535a954ffa1ee7d8 (patch) | |
| tree | 0e583bf78ddea68200b42020680ee80de52d2e55 /arch/x86/kvm/vmx/pmu_intel.c | |
| parent | 68fb4757e8678894530ee0b15c29a3567207b970 (diff) | |
KVM: x86/pmu: Defer counter emulated overflow via pmc->prev_counter
Defer reprogramming counters and handling overflow via KVM_REQ_PMU
when incrementing counters. KVM skips emulated WRMSR in the VM-Exit
fastpath, the fastpath runs with IRQs disabled, skipping instructions
can increment and reprogram counters, reprogramming counters can
sleep, and sleeping is disallowed while IRQs are disabled.
[*] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
[*] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 2981888, name: CPU 15/KVM
[*] preempt_count: 1, expected: 0
[*] RCU nest depth: 0, expected: 0
[*] INFO: lockdep is turned off.
[*] irq event stamp: 0
[*] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[*] hardirqs last disabled at (0): [<ffffffff8121222a>] copy_process+0x146a/0x62d0
[*] softirqs last enabled at (0): [<ffffffff81212269>] copy_process+0x14a9/0x62d0
[*] softirqs last disabled at (0): [<0000000000000000>] 0x0
[*] Preemption disabled at:
[*] [<ffffffffc2063fc1>] vcpu_enter_guest+0x1001/0x3dc0 [kvm]
[*] CPU: 17 PID: 2981888 Comm: CPU 15/KVM Kdump: 5.19.0-rc1-g239111db364c-dirty #2
[*] Call Trace:
[*] <TASK>
[*] dump_stack_lvl+0x6c/0x9b
[*] __might_resched.cold+0x22e/0x297
[*] __mutex_lock+0xc0/0x23b0
[*] perf_event_ctx_lock_nested+0x18f/0x340
[*] perf_event_pause+0x1a/0x110
[*] reprogram_counter+0x2af/0x1490 [kvm]
[*] kvm_pmu_trigger_event+0x429/0x950 [kvm]
[*] kvm_skip_emulated_instruction+0x48/0x90 [kvm]
[*] handle_fastpath_set_msr_irqoff+0x349/0x3b0 [kvm]
[*] vmx_vcpu_run+0x268e/0x3b80 [kvm_intel]
[*] vcpu_enter_guest+0x1d22/0x3dc0 [kvm]
Add a field to kvm_pmc to track the previous counter value in order
to defer overflow detection to kvm_pmu_handle_event() (the counter must
be paused before handling overflow, and that may increment the counter).
Opportunistically shrink sizeof(struct kvm_pmc) a bit.
Suggested-by: Wanpeng Li <wanpengli@tencent.com>
Fixes: 9cd803d496e7 ("KVM: x86: Update vPMCs when retiring instructions")
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-6-likexu@tencent.com
[sean: avoid re-triggering KVM_REQ_PMU on overflow, tweak changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220923001355.3741194-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/pmu_intel.c')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 6c80dff37b77..e5cec07ca8d9 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -646,14 +646,14 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu) pmc = &pmu->gp_counters[i]; pmc_stop_counter(pmc); - pmc->counter = pmc->eventsel = 0; + pmc->counter = pmc->prev_counter = pmc->eventsel = 0; } for (i = 0; i < KVM_PMC_MAX_FIXED; i++) { pmc = &pmu->fixed_counters[i]; pmc_stop_counter(pmc); - pmc->counter = 0; + pmc->counter = pmc->prev_counter = 0; } pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = 0; |