From: Yosry Ahmed <yosry.ahmed@linux.dev>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: [PATCH 5/7] KVM: SVM: Flush the ASID when running on a new CPU
Date: Thu, 13 Mar 2025 21:55:38 +0000 [thread overview]
Message-ID: <20250313215540.4171762-6-yosry.ahmed@linux.dev> (raw)
In-Reply-To: <20250313215540.4171762-1-yosry.ahmed@linux.dev>
Currently, when a vCPU is migrated to a new physical CPU, the ASID
generation is reset to trigger allocating a new ASID. In preparation for
using a static ASID per VM, just flush the ASID in this case (falling
back to flushing everything if FLUSBYASID is not available).
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
arch/x86/kvm/svm/svm.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e5064fbefb822..b8a3fc81fc9c8 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3626,12 +3626,12 @@ static int pre_svm_run(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
/*
- * If the previous vmrun of the vmcb occurred on a different physical
- * cpu, then mark the vmcb dirty and assign a new asid. Hardware's
- * vmcb clean bits are per logical CPU, as are KVM's asid assignments.
+ * If the previous VMRUN of the VMCB occurred on a different physical
+ * CPU, then mark the VMCB dirty and flush the ASID. Hardware's
+ * VMCB clean bits are per logical CPU, as are KVM's ASID assignments.
*/
if (unlikely(svm->current_vmcb->cpu != vcpu->cpu)) {
- svm->current_vmcb->asid_generation = 0;
+ svm_vmcb_set_flush_asid(svm->vmcb);
vmcb_mark_all_dirty(svm->vmcb);
svm->current_vmcb->cpu = vcpu->cpu;
}
--
2.49.0.rc1.451.g8f38331e32-goog
next prev parent reply other threads:[~2025-03-13 21:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-13 21:55 [PATCH 0/7] Make ASIDs static for SVM Yosry Ahmed
2025-03-13 21:55 ` [PATCH 1/7] KVM: VMX: Generalize VPID allocation to be vendor-neutral Yosry Ahmed
2025-03-13 21:55 ` [PATCH 2/7] KVM: SVM: Use cached local variable in init_vmcb() Yosry Ahmed
2025-03-13 21:55 ` [PATCH 3/7] KVM: SVM: Add helpers to set/clear ASID flush Yosry Ahmed
2025-03-13 21:55 ` [PATCH 4/7] KVM: SVM: Flush everything if FLUSHBYASID is not available Yosry Ahmed
2025-03-13 21:55 ` Yosry Ahmed [this message]
2025-03-13 21:55 ` [PATCH 6/7] KVM: SVM: Use a single ASID per VM Yosry Ahmed
2025-03-14 0:47 ` Yosry Ahmed
2025-03-17 21:11 ` Yosry Ahmed
2025-03-17 21:44 ` Jim Mattson
2025-03-17 22:13 ` Yosry Ahmed
2025-03-13 21:55 ` [PATCH 7/7] KVM: SVM: Share more code between pre_sev_run() and pre_svm_run() Yosry Ahmed
2025-03-17 19:36 ` Yosry Ahmed
2025-03-20 18:17 ` [PATCH 0/7] Make ASIDs static for SVM Yosry Ahmed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250313215540.4171762-6-yosry.ahmed@linux.dev \
--to=yosry.ahmed@linux.dev \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mlevitsk@redhat.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox