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| author | Paolo Bonzini <pbonzini@redhat.com> | 2026-05-30 19:55:42 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2026-06-12 11:43:52 +0300 |
| commit | 9eff3e99a81c20148b934d5fe882bcfe7c6078ff (patch) | |
| tree | 430dde01ed7debb0ac64a1686e5856de4db5f383 | |
| parent | 8503953e266c78e4bbe281ea3a0a06b1a37b7836 (diff) | |
| download | linux-9eff3e99a81c20148b934d5fe882bcfe7c6078ff.tar.xz | |
KVM: nVMX: remove unnecessary code in prepare_vmcs02_rare
The early vmwrite of the PDPTRs in prepare_vmcs02_rare() is redundant, because
every write it does will be performed by prepare_vmcs02() if it is actually
needed.
In any case where the emulator or the processor need the PDPTR, either
is_pae_paging() is true on vmentry, or a write of CR0, CR4 or EFER will
cause a vmexit to L0. The next vmentry will refresh the PDPTRs in the
vmcs02 from vmcs12.
In fact, the original version[1] of what ended up being commit
c7554efc8335 ("KVM: nVMX: Copy PDPTRs to/from vmcs12 only when
necessary"), the writes in what is now prepare_vmcs02_rare() were removed.
When the mega-collection of optimizations was posted[2], the removal of
that code got dropped as a rebase good, so reinstate it.
[1] https://lore.kernel.org/all/20190507160640.4812-16-sean.j.christopherson@intel.com
[2] https://lore.kernel.org/all/1560445409-17363-31-git-send-email-pbonzini@redhat.com
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20260530165545.25599-3-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 11 |
1 files changed, 0 insertions, 11 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 4690a4d23709..1bd0839146fd 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2623,17 +2623,6 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12) vmcs_writel(GUEST_SYSENTER_ESP, vmcs12->guest_sysenter_esp); vmcs_writel(GUEST_SYSENTER_EIP, vmcs12->guest_sysenter_eip); - /* - * L1 may access the L2's PDPTR, so save them to construct - * vmcs12 - */ - if (enable_ept) { - vmcs_write64(GUEST_PDPTR0, vmcs12->guest_pdptr0); - vmcs_write64(GUEST_PDPTR1, vmcs12->guest_pdptr1); - vmcs_write64(GUEST_PDPTR2, vmcs12->guest_pdptr2); - vmcs_write64(GUEST_PDPTR3, vmcs12->guest_pdptr3); - } - if (kvm_mpx_supported() && vmx->vcpu.arch.nested_run_pending && (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)) vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs); |