linux-kernel - [PATCH 03/33] KVM: x86: Don't load/put vCPU when unloading its MMU during teardown

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250226181453.2311849-4-pbonzini@redhat.com>
Date: Wed, 26 Feb 2025 13:14:22 -0500
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: seanjc@...gle.com,
	Yan Zhao <yan.y.zhao@...el.com>,
	Rick Edgecombe <rick.p.edgecombe@...el.com>
Subject: [PATCH 03/33] KVM: x86: Don't load/put vCPU when unloading its MMU during teardown

From: Sean Christopherson <seanjc@...gle.com>

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@...gle.com>
Message-ID: <20250224235542.2562848-5-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.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 514fc84efc92..e5cdcccac4c9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12754,13 +12754,6 @@ 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;
@@ -12768,7 +12761,7 @@ 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);
 	}
 }
 
-- 
2.43.5