Re: [PATCH 4/7] KVM: x86: Don't load/put vCPU when unloading its MMU during teardown
From: Yan Zhao <hidden>
Date: 2025-02-25 07:15:00
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, linux-riscv, linuxppc-dev, lkml, loongarch
On Mon, Feb 24, 2025 at 03:55:39PM -0800, Sean Christopherson wrote:
quoted hunk ↗ jump to hunk
Don't load (and then put) a vCPU when unloading its MMU during VM destruction, as nothing in kvm_mmu_unload() accesses vCPU state beyond the root page/address of each MMU, i.e. can't possible need to run with the vCPU loaded. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/x86.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 045c61cc7e54..9978ed4c0917 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c@@ -12767,13 +12767,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) return ret; } -static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) -{ - vcpu_load(vcpu); - kvm_mmu_unload(vcpu); - vcpu_put(vcpu); -} - static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i;@@ -12781,7 +12774,7 @@ static void kvm_unload_vcpu_mmus(struct kvm *kvm) kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); - kvm_unload_vcpu_mmu(vcpu); + kvm_mmu_unload(vcpu);
What about just dropping kvm_unload_vcpu_mmu() here? kvm_mmu_unload() will be invoked again in kvm_mmu_destroy(). kvm_arch_vcpu_destroy() --> kvm_mmu_destroy() --> kvm_mmu_unload().
} } -- 2.48.1.658.g4767266eb4-goog