Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH MANUALSEL 5.15 5/7] KVM: x86: Do not change ICR on write to APIC_SELF_IPI | Date | Wed, 27 Apr 2022 11:54:25 -0400 |
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From: Paolo Bonzini <pbonzini@redhat.com>
[ Upstream commit d22a81b304a27fca6124174a8e842e826c193466 ]
Emulating writes to SELF_IPI with a write to ICR has an unwanted side effect: the value of ICR in vAPIC page gets changed. The lists SELF_IPI as write-only, with no associated MMIO offset, so any write should have no visible side effect in the vAPIC page.
Reported-by: Chao Gao <chao.gao@intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/x86/kvm/lapic.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 4d92fb4fdf69..83d1743a1dd0 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2125,10 +2125,9 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) break; case APIC_SELF_IPI: - if (apic_x2apic_mode(apic)) { - kvm_lapic_reg_write(apic, APIC_ICR, - APIC_DEST_SELF | (val & APIC_VECTOR_MASK)); - } else + if (apic_x2apic_mode(apic)) + kvm_apic_send_ipi(apic, APIC_DEST_SELF | (val & APIC_VECTOR_MASK), 0); + else ret = 1; break; default: -- 2.35.1
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