lkml.org 
[lkml]   [2022]   [Sep]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v4 18/32] KVM: x86: Explicitly skip optimized logical map setup if vCPU's LDR==0
From
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;
--
2.38.0.rc1.362.ged0d419d3c-goog
\
 
 \ /
  Last update: 2022-10-01 03:03    [W:0.230 / U:0.664 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site