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KVM: x86: Mask LVTPC when handling a PMI
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stable inclusion
from stable-v5.10.199
commit 459af3fb81e6e2f6cf8ea7b67f3b9062b0361f96
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9AWJ5

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=459af3fb81e6e2f6cf8ea7b67f3b9062b0361f96

--------------------------------

commit a16eb25 upstream.

Per the SDM, "When the local APIC handles a performance-monitoring
counters interrupt, it automatically sets the mask flag in the LVT
performance counter register."  Add this behavior to KVM's local APIC
emulation.

Failure to mask the LVTPC entry results in spurious PMIs, e.g. when
running Linux as a guest, PMI handlers that do a "late_ack" spew a large
number of "dazed and confused" spurious NMI warnings.

Fixes: f5132b0 ("KVM: Expose a version 2 architectural PMU to a guests")
Cc: stable@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
Tested-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230925173448.3518223-3-mizhang@google.com
[sean: massage changelog, correct Fixes]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>
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jsmattsonjr authored and sanglipeng1 committed Mar 25, 2024
1 parent 7eb7623 commit ccd7445
Showing 1 changed file with 6 additions and 2 deletions.
8 changes: 6 additions & 2 deletions arch/x86/kvm/lapic.c
Original file line number Diff line number Diff line change
Expand Up @@ -2408,13 +2408,17 @@ int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type)
{
u32 reg = kvm_lapic_get_reg(apic, lvt_type);
int vector, mode, trig_mode;
int r;

if (kvm_apic_hw_enabled(apic) && !(reg & APIC_LVT_MASKED)) {
vector = reg & APIC_VECTOR_MASK;
mode = reg & APIC_MODE_MASK;
trig_mode = reg & APIC_LVT_LEVEL_TRIGGER;
return __apic_accept_irq(apic, mode, vector, 1, trig_mode,
NULL);

r = __apic_accept_irq(apic, mode, vector, 1, trig_mode, NULL);
if (r && lvt_type == APIC_LVTPC)
kvm_lapic_set_reg(apic, APIC_LVTPC, reg | APIC_LVT_MASKED);
return r;
}
return 0;
}
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