KVM: nVMX: Switch to vmcs01 to update TPR threshold on-demand if L2 is active

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If KVM updates L1's TPR Threshold while L2 is active, temporarily load
vmcs01 and immediately update TPR_THRESHOLD instead of deferring the
update until the next nested VM-Exit.  Deferring the TPR Threshold update
is relatively straightforward, but for several APICv related updates,
deferring updates creates ordering and state consistency problems, e.g.
KVM at-large thinks APICv is enabled, but vmcs01 is still running with
stale (and effectively unknown) state.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://patch.msgid.link/20260109034532.1012993-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Sean Christopherson 2026-01-08 19:45:27 -08:00

parent 3e013d0a70

commit 51ca274607

3 changed files with 3 additions and 11 deletions

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4

arch/x86/kvm/vmx/nested.c

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7

arch/x86/kvm/vmx/vmx.c

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3

arch/x86/kvm/vmx/vmx.h

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