The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x fb71c795935652fa20eaf9517ca9547f5af99a76 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025031034-twister-stash-ba87@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fb71c795935652fa20eaf9517ca9547f5af99a76 Mon Sep 17 00:00:00 2001 From: Sean Christopherson seanjc@google.com Date: Thu, 27 Feb 2025 14:24:08 -0800 Subject: [PATCH] KVM: x86: Snapshot the host's DEBUGCTL in common x86
Move KVM's snapshot of DEBUGCTL to kvm_vcpu_arch and take the snapshot in common x86, so that SVM can also use the snapshot.
Opportunistically change the field to a u64. While bits 63:32 are reserved on AMD, not mentioned at all in Intel's SDM, and managed as an "unsigned long" by the kernel, DEBUGCTL is an MSR and therefore a 64-bit value.
Reviewed-by: Xiaoyao Li xiaoyao.li@intel.com Cc: stable@vger.kernel.org Reviewed-and-tested-by: Ravi Bangoria ravi.bangoria@amd.com Link: https://lore.kernel.org/r/20250227222411.3490595-4-seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0b7af5902ff7..32ae3aa50c7e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -780,6 +780,7 @@ struct kvm_vcpu_arch { u32 pkru; u32 hflags; u64 efer; + u64 host_debugctl; u64 apic_base; struct kvm_lapic *apic; /* kernel irqchip context */ bool load_eoi_exitmap_pending; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 6c56d5235f0f..3b92f893b239 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1514,16 +1514,12 @@ void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu, */ void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { - struct vcpu_vmx *vmx = to_vmx(vcpu); - if (vcpu->scheduled_out && !kvm_pause_in_guest(vcpu->kvm)) shrink_ple_window(vcpu);
vmx_vcpu_load_vmcs(vcpu, cpu, NULL);
vmx_vcpu_pi_load(vcpu, cpu); - - vmx->host_debugctlmsr = get_debugctlmsr(); }
void vmx_vcpu_put(struct kvm_vcpu *vcpu) @@ -7458,8 +7454,8 @@ fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit) }
/* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */ - if (vmx->host_debugctlmsr) - update_debugctlmsr(vmx->host_debugctlmsr); + if (vcpu->arch.host_debugctl) + update_debugctlmsr(vcpu->arch.host_debugctl);
#ifndef CONFIG_X86_64 /* diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 8b111ce1087c..951e44dc9d0e 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -340,8 +340,6 @@ struct vcpu_vmx { /* apic deadline value in host tsc */ u64 hv_deadline_tsc;
- unsigned long host_debugctlmsr; - /* * Only bits masked by msr_ia32_feature_control_valid_bits can be set in * msr_ia32_feature_control. FEAT_CTL_LOCKED is always included diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 02159c967d29..5c6fd0edc41f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4968,6 +4968,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
/* Save host pkru register if supported */ vcpu->arch.host_pkru = read_pkru(); + vcpu->arch.host_debugctl = get_debugctlmsr();
/* Apply any externally detected TSC adjustments (due to suspend) */ if (unlikely(vcpu->arch.tsc_offset_adjustment)) {