From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Chao Gao <chao.gao@intel.com>,
Sean Christopherson <seanjc@google.com>,
Sasha Levin <sashal@kernel.org>,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, kvm@vger.kernel.org
Subject: [PATCH MANUALSEL 5.17 4/7] KVM: x86: Do not change ICR on write to APIC_SELF_IPI
Date: Wed, 27 Apr 2022 11:54:00 -0400 [thread overview]
Message-ID: <20220427155408.19352-4-sashal@kernel.org> (raw)
In-Reply-To: <20220427155408.19352-1-sashal@kernel.org>
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 2a10d0033c96..6b6f9359d29e 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
next prev parent reply other threads:[~2022-04-27 15:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 15:53 [PATCH MANUALSEL 5.17 1/7] kvm: selftests: do not use bitfields larger than 32-bits for PTEs Sasha Levin
2022-04-27 15:53 ` [PATCH MANUALSEL 5.17 2/7] KVM: selftests: Silence compiler warning in the kvm_page_table_test Sasha Levin
2022-04-27 16:16 ` Paolo Bonzini
2022-04-27 15:53 ` [PATCH MANUALSEL 5.17 3/7] x86/kvm: Preserve BSP MSR_KVM_POLL_CONTROL across suspend/resume Sasha Levin
2022-04-27 16:16 ` Paolo Bonzini
2022-04-27 15:54 ` Sasha Levin [this message]
2022-04-27 16:16 ` [PATCH MANUALSEL 5.17 4/7] KVM: x86: Do not change ICR on write to APIC_SELF_IPI Paolo Bonzini
2022-04-27 15:54 ` [PATCH MANUALSEL 5.17 5/7] KVM: x86/mmu: avoid NULL-pointer dereference on page freeing bugs Sasha Levin
2022-04-27 16:16 ` Paolo Bonzini
2022-04-27 15:54 ` [PATCH MANUALSEL 5.17 6/7] KVM: SEV: Allow SEV intra-host migration of VM with mirrors Sasha Levin
2022-04-27 16:04 ` Paolo Bonzini
2022-04-27 15:54 ` [PATCH MANUALSEL 5.17 7/7] KVM: LAPIC: Enable timer posted-interrupt only when mwait/hlt is advertised Sasha Levin
2022-04-27 16:17 ` Paolo Bonzini
2022-04-27 16:16 ` [PATCH MANUALSEL 5.17 1/7] kvm: selftests: do not use bitfields larger than 32-bits for PTEs Paolo Bonzini
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