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Subject[PATCH 1/6] KVM: x86: Inject #GP if WRMSR sets reserved bits in APIC Self-IPI
From
Inject a #GP if the guest attempts to set reserved bits in the x2APIC-only
Self-IPI register. Bits 7:0 hold the vector, all other bits are reserved.

Reported-by: Marc Orr <marcorr@google.com>
Cc: Ben Gardon <bgardon@google.com>
Cc: Venkatesh Srinivas <venkateshs@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/lapic.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 80f92cbc4029..f77da92c6ea6 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2315,10 +2315,14 @@ static int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
break;

case APIC_SELF_IPI:
- if (apic_x2apic_mode(apic))
- kvm_apic_send_ipi(apic, APIC_DEST_SELF | (val & APIC_VECTOR_MASK), 0);
- else
+ /*
+ * Self-IPI exists only when x2APIC is enabled. Bits 7:0 hold
+ * the vector, everything else is reserved.
+ */
+ if (!apic_x2apic_mode(apic) || (val & ~APIC_VECTOR_MASK))
ret = 1;
+ else
+ kvm_apic_send_ipi(apic, APIC_DEST_SELF | val, 0);
break;
default:
ret = 1;
--
2.39.0.314.g84b9a713c41-goog
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