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KVM: x86: Mark x2APIC DFR reg as non-existent for x2APIC

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Mark APIC_DFR as being invalid/non-existent in x2APIC mode instead of
handling it as a one-off check in kvm_x2apic_msr_read().  This will allow
reusing "valid_reg_mask" to generate VMX's interception bitmaps for
x2APIC.  Handling DFR in the common read path may also fix the Hyper-V
PV MSR interface, if that can coexist with x2APIC.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20230107011025.565472-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2023-01-07 01:10:22 +00:00
parent ab52be1b31
commit b223649576
1 changed files with 4 additions and 7 deletions
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11
arch/x86/kvm/lapic.c
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@ -1573,7 +1573,6 @@ static int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
APIC_REG_MASK(APIC_TASKPRI) |
APIC_REG_MASK(APIC_PROCPRI) |
APIC_REG_MASK(APIC_LDR) |
APIC_REG_MASK(APIC_DFR) |
APIC_REG_MASK(APIC_SPIV) |
APIC_REGS_MASK(APIC_ISR, APIC_ISR_NR) |
APIC_REGS_MASK(APIC_TMR, APIC_ISR_NR) |
@ -1594,12 +1593,13 @@ static int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
valid_reg_mask |= APIC_REG_MASK(APIC_LVTCMCI);
/*
* ARBPRI and ICR2 are not valid in x2APIC mode. WARN if KVM reads ICR
* in x2APIC mode as it's an 8-byte register in x2APIC and needs to be
* manually handled by the caller.
* ARBPRI, DFR, and ICR2 are not valid in x2APIC mode. WARN if KVM
* reads ICR in x2APIC mode as it's an 8-byte register in x2APIC and
* needs to be manually handled by the caller.
*/
if (!apic_x2apic_mode(apic))
valid_reg_mask |= APIC_REG_MASK(APIC_ARBPRI) |
APIC_REG_MASK(APIC_DFR) |
APIC_REG_MASK(APIC_ICR2);
else
WARN_ON_ONCE(offset == APIC_ICR);
@ -3147,9 +3147,6 @@ int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(apic))
return 1;
if (reg == APIC_DFR)
return 1;
return kvm_lapic_msr_read(apic, reg, data);
}