| Message ID | 20221001005915.2041642-19-seanjc@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: AVIC and local APIC fixes+cleanups | expand |
On Sat, 2022-10-01 at 00:59 +0000, Sean Christopherson wrote: > Explicitly skip the optimized map setup if the vCPU's LDR is '0', i.e. if > the vCPU will never respond to logical mode interrupts. KVM already > skips setup in this case, but relies on kvm_apic_map_get_logical_dest() > to generate mask==0. KVM still needs the mask=0 check as a non-zero LDR > can yield mask==0 depending on the mode, but explicitly handling the LDR > will make it simpler to clean up the logical mode tracking in the future. > > No functional change intended. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/lapic.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 42b61469674d..cef8b202490b 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -286,10 +286,12 @@ void kvm_recalculate_apic_map(struct kvm *kvm) > continue; > > ldr = kvm_lapic_get_reg(apic, APIC_LDR); > + if (!ldr) > + continue; > > if (apic_x2apic_mode(apic)) { > new->mode |= KVM_APIC_MODE_X2APIC; > - } else if (ldr) { > + } else { > ldr = GET_APIC_LOGICAL_ID(ldr); > if (kvm_lapic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT) > new->mode |= KVM_APIC_MODE_XAPIC_FLAT; Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Best regards, Maxim Levitsky
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 42b61469674d..cef8b202490b 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -286,10 +286,12 @@ void kvm_recalculate_apic_map(struct kvm *kvm) continue; ldr = kvm_lapic_get_reg(apic, APIC_LDR); + if (!ldr) + continue; if (apic_x2apic_mode(apic)) { new->mode |= KVM_APIC_MODE_X2APIC; - } else if (ldr) { + } else { ldr = GET_APIC_LOGICAL_ID(ldr); if (kvm_lapic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT) new->mode |= KVM_APIC_MODE_XAPIC_FLAT;
Explicitly skip the optimized map setup if the vCPU's LDR is '0', i.e. if the vCPU will never respond to logical mode interrupts. KVM already skips setup in this case, but relies on kvm_apic_map_get_logical_dest() to generate mask==0. KVM still needs the mask=0 check as a non-zero LDR can yield mask==0 depending on the mode, but explicitly handling the LDR will make it simpler to clean up the logical mode tracking in the future. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/lapic.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)