From: Brendan Jackman <jackmanb@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>
Cc: <kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Brendan Jackman <jackmanb@google.com>
Subject: Re: [PATCH v5 1/9] KVM: VMX: Use on-stack copy of @flags in __vmx_vcpu_run()
Date: Fri, 14 Nov 2025 12:36:01 +0000 [thread overview]
Message-ID: <DE8F7MGETJP2.K6A8JKD8LV4A@google.com> (raw)
In-Reply-To: <20251113233746.1703361-2-seanjc@google.com>
On Thu Nov 13, 2025 at 11:37 PM UTC, Sean Christopherson wrote:
> When testing for VMLAUNCH vs. VMRESUME, use the copy of @flags from the
> stack instead of first moving it to EBX, and then propagating
> VMX_RUN_VMRESUME to RFLAGS.CF (because RBX is clobbered with the guest
> value prior to the conditional branch to VMLAUNCH). Stashing information
> in RFLAGS is gross, especially with the writer and reader being bifurcated
> by yet more gnarly assembly code.
>
> Opportunistically drop the SHIFT macros as they existed purely to allow
> the VM-Enter flow to use Bit Test.
>
> Suggested-by: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
next prev parent reply other threads:[~2025-11-14 12:36 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-13 23:37 [PATCH v5 0/9] x86/bugs: KVM: L1TF and MMIO Stale Data cleanups Sean Christopherson
2025-11-13 23:37 ` [PATCH v5 1/9] KVM: VMX: Use on-stack copy of @flags in __vmx_vcpu_run() Sean Christopherson
2025-11-14 12:36 ` Brendan Jackman [this message]
2025-11-14 15:06 ` Uros Bizjak
2025-11-19 0:29 ` Sean Christopherson
2025-11-14 16:40 ` Borislav Petkov
2025-11-13 23:37 ` [PATCH v5 2/9] x86/bugs: Use VM_CLEAR_CPU_BUFFERS in VMX as well Sean Christopherson
2025-11-14 12:40 ` Brendan Jackman
2025-11-13 23:37 ` [PATCH v5 3/9] x86/bugs: Decouple ALTERNATIVE usage from VERW macro definition Sean Christopherson
2025-11-17 10:11 ` Borislav Petkov
2025-11-17 15:33 ` Sean Christopherson
2025-11-18 10:32 ` Borislav Petkov
2025-11-13 23:37 ` [PATCH v5 4/9] x86/bugs: Use an x86 feature to track the MMIO Stale Data mitigation Sean Christopherson
2025-11-13 23:37 ` [PATCH v5 5/9] KVM: VMX: Handle MMIO Stale Data in VM-Enter assembly via ALTERNATIVES_2 Sean Christopherson
2025-11-14 12:55 ` Brendan Jackman
2025-11-13 23:37 ` [PATCH v5 6/9] x86/bugs: KVM: Move VM_CLEAR_CPU_BUFFERS into SVM as SVM_CLEAR_CPU_BUFFERS Sean Christopherson
2025-11-13 23:37 ` [PATCH v5 7/9] KVM: VMX: Bundle all L1 data cache flush mitigation code together Sean Christopherson
2025-11-13 23:37 ` [PATCH v5 8/9] KVM: VMX: Disable L1TF L1 data cache flush if CONFIG_CPU_MITIGATIONS=n Sean Christopherson
2025-11-13 23:37 ` [PATCH v5 9/9] KVM: x86: Unify L1TF flushing under per-CPU variable Sean Christopherson
2025-11-21 18:55 ` [PATCH v5 0/9] x86/bugs: KVM: L1TF and MMIO Stale Data cleanups Sean Christopherson
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