[PATCH] KVM: TDX: Fix APIC MSR ranges in tdx_has_emulated_msr()

[Dmytro Maluka]

Note: compile-tested only. Bug found by code inspection.

X2APIC_MSR(APIC_xxx + APIC_ISR_NR) is incorrect, since APIC_ISR_NR is
0x8, not 0x80, so shifting it in X2APIC_MSR() results in losing those
lower bits, making it simply equal to X2APIC_MSR(APIC_xxx), i.e. making
the entire range consist of APIC_xxx only. So adding APIC_ISR_NR needs
to be outside X2APIC_MSR().

Additionally, since "..." ranges are inclusive, need to subtract 1.

Fixes: dd50294f3e3c ("KVM: TDX: Implement callbacks for MSR operations")
Signed-off-by: Dmytro Maluka <dmaluka@xxxxxxxxxxxx>
---
 arch/x86/kvm/vmx/tdx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index c5065f84b78b..466a7de660c2 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2136,9 +2136,9 @@ bool tdx_has_emulated_msr(u32 index)
 		case X2APIC_MSR(APIC_TASKPRI):
 		case X2APIC_MSR(APIC_PROCPRI):
 		case X2APIC_MSR(APIC_EOI):
-		case X2APIC_MSR(APIC_ISR) ... X2APIC_MSR(APIC_ISR + APIC_ISR_NR):
-		case X2APIC_MSR(APIC_TMR) ... X2APIC_MSR(APIC_TMR + APIC_ISR_NR):
-		case X2APIC_MSR(APIC_IRR) ... X2APIC_MSR(APIC_IRR + APIC_ISR_NR):
+		case X2APIC_MSR(APIC_ISR) ... X2APIC_MSR(APIC_ISR) + APIC_ISR_NR - 1:
+		case X2APIC_MSR(APIC_TMR) ... X2APIC_MSR(APIC_TMR) + APIC_ISR_NR - 1:
+		case X2APIC_MSR(APIC_IRR) ... X2APIC_MSR(APIC_IRR) + APIC_ISR_NR - 1:
 			return false;
 		default:
 			return true;
-- 
2.53.0.851.ga537e3e6e9-goog