From 38ee66cb1845dbf1e97c5e5d3db01ae4513f66a9 Mon Sep 17 00:00:00 2001 From: Brendan Jackman Date: Thu, 13 Nov 2025 15:37:46 -0800 Subject: KVM: x86: Unify L1TF flushing under per-CPU variable Currently the tracking of the need to flush L1D for L1TF is tracked by two bits: one per-CPU and one per-vCPU. The per-vCPU bit is always set when the vCPU shows up on a core, so there is no interesting state that's truly per-vCPU. Indeed, this is a requirement, since L1D is a part of the physical CPU. So simplify this by combining the two bits. The vCPU bit was being written from preemption-enabled regions. To play nice with those cases, wrap all calls from KVM and use a raw write so that request a flush with preemption enabled doesn't trigger what would effectively be DEBUG_PREEMPT false positives. Preemption doesn't need to be disabled, as kvm_arch_vcpu_load() will mark the new CPU as needing a flush if the vCPU task is migrated, or if userspace runs the vCPU on a different task. Signed-off-by: Brendan Jackman [sean: put raw write in KVM instead of in a hardirq.h variant] Link: https://patch.msgid.link/20251113233746.1703361-10-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 692ec922945f..103af57e1060 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1055,9 +1055,6 @@ struct kvm_vcpu_arch { /* be preempted when it's in kernel-mode(cpl=0) */ bool preempted_in_kernel; - /* Flush the L1 Data cache for L1TF mitigation on VMENTER */ - bool l1tf_flush_l1d; - /* Host CPU on which VM-entry was most recently attempted */ int last_vmentry_cpu; -- cgit v1.2.3