From: Sean Christopherson <seanjc@google.com>
To: Sasha Levin <sashal@kernel.org>
Cc: stable@vger.kernel.org
Subject: Re: [PATCH 6.16.y 2/6] KVM: x86: Drop kvm_x86_ops.set_dr6() in favor of a new KVM_RUN flag
Date: Thu, 14 Aug 2025 11:14:34 -0700 [thread overview]
Message-ID: <aJ4nitwghGrnj5Xs@google.com> (raw)
In-Reply-To: <20250814161212.2107674-2-sashal@kernel.org>
On Thu, Aug 14, 2025, Sasha Levin wrote:
> From: Sean Christopherson <seanjc@google.com>
>
> [ Upstream commit 80c64c7afea1da6a93ebe88d3d29d8a60377ef80 ]
>
> Instruct vendor code to load the guest's DR6 into hardware via a new
> KVM_RUN flag, and remove kvm_x86_ops.set_dr6(), whose sole purpose was to
> load vcpu->arch.dr6 into hardware when DR6 can be read/written directly
> by the guest.
>
> Note, TDX already WARNs on any run_flag being set, i.e. will yell if KVM
> thinks DR6 needs to be reloaded. TDX vCPUs force KVM_DEBUGREG_AUTO_SWITCH
> and never clear the flag, i.e. should never observe KVM_RUN_LOAD_GUEST_DR6.
>
> Cc: stable@vger.kernel.org
> Link: https://lore.kernel.org/r/20250610232010.162191-4-seanjc@google.com
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Stable-dep-of: 6b1dd26544d0 ("KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
Acked-by: Sean Christopherson <seanjc@google.com>
next prev parent reply other threads:[~2025-08-14 18:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-12 16:15 FAILED: patch "[PATCH] KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while" failed to apply to 6.16-stable tree gregkh
2025-08-14 16:12 ` [PATCH 6.16.y 1/6] KVM: x86: Convert vcpu_run()'s immediate exit param into a generic bitmap Sasha Levin
2025-08-14 16:12 ` [PATCH 6.16.y 2/6] KVM: x86: Drop kvm_x86_ops.set_dr6() in favor of a new KVM_RUN flag Sasha Levin
2025-08-14 18:14 ` Sean Christopherson [this message]
2025-08-14 16:12 ` [PATCH 6.16.y 3/6] KVM: VMX: Extract checking of guest's DEBUGCTL into helper Sasha Levin
2025-08-14 18:14 ` Sean Christopherson
2025-08-14 16:12 ` [PATCH 6.16.y 4/6] KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter Sasha Levin
2025-08-14 18:15 ` Sean Christopherson
2025-08-14 16:12 ` [PATCH 6.16.y 5/6] KVM: VMX: Wrap all accesses to IA32_DEBUGCTL with getter/setter APIs Sasha Levin
2025-08-14 18:15 ` Sean Christopherson
2025-08-14 16:12 ` [PATCH 6.16.y 6/6] KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest Sasha Levin
2025-08-14 18:15 ` Sean Christopherson
2025-08-14 18:14 ` [PATCH 6.16.y 1/6] KVM: x86: Convert vcpu_run()'s immediate exit param into a generic bitmap Sean Christopherson
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