From: Sean Christopherson <seanjc@google.com>
To: stable@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sasha Levin <sashal@kernel.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 6.12.y 6/7] KVM: VMX: Wrap all accesses to IA32_DEBUGCTL with getter/setter APIs
Date: Thu, 14 Aug 2025 17:57:24 -0700 [thread overview]
Message-ID: <20250815005725.2386187-7-seanjc@google.com> (raw)
In-Reply-To: <20250815005725.2386187-1-seanjc@google.com>
From: Maxim Levitsky <mlevitsk@redhat.com>
[ Upstream commit 7d0cce6cbe71af6e9c1831bff101a2b9c249c4a2 ]
Introduce vmx_guest_debugctl_{read,write}() to handle all accesses to
vmcs.GUEST_IA32_DEBUGCTL. This will allow stuffing FREEZE_IN_SMM into
GUEST_IA32_DEBUGCTL based on the host setting without bleeding the state
into the guest, and without needing to copy+paste the FREEZE_IN_SMM
logic into every patch that accesses GUEST_IA32_DEBUGCTL.
No functional change intended.
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
[sean: massage changelog, make inline, use in all prepare_vmcs02() cases]
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20250610232010.162191-8-seanjc@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/nested.c | 10 +++++-----
arch/x86/kvm/vmx/pmu_intel.c | 8 ++++----
arch/x86/kvm/vmx/vmx.c | 8 +++++---
arch/x86/kvm/vmx/vmx.h | 10 ++++++++++
4 files changed, 24 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1e0b9f92ff18..9a336f661fc6 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2653,11 +2653,11 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
if (vmx->nested.nested_run_pending &&
(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) {
kvm_set_dr(vcpu, 7, vmcs12->guest_dr7);
- vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl &
- vmx_get_supported_debugctl(vcpu, false));
+ vmx_guest_debugctl_write(vcpu, vmcs12->guest_ia32_debugctl &
+ vmx_get_supported_debugctl(vcpu, false));
} else {
kvm_set_dr(vcpu, 7, vcpu->arch.dr7);
- vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.pre_vmenter_debugctl);
+ vmx_guest_debugctl_write(vcpu, vmx->nested.pre_vmenter_debugctl);
}
if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending ||
!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)))
@@ -3527,7 +3527,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
if (!vmx->nested.nested_run_pending ||
!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
- vmx->nested.pre_vmenter_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL);
+ vmx->nested.pre_vmenter_debugctl = vmx_guest_debugctl_read();
if (kvm_mpx_supported() &&
(!vmx->nested.nested_run_pending ||
!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)))
@@ -4774,7 +4774,7 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
__vmx_set_segment(vcpu, &seg, VCPU_SREG_LDTR);
kvm_set_dr(vcpu, 7, 0x400);
- vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
+ vmx_guest_debugctl_write(vcpu, 0);
if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
vmcs12->vm_exit_msr_load_count))
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 9c9d4a336166..a5edc623166a 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -605,11 +605,11 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu)
*/
static void intel_pmu_legacy_freezing_lbrs_on_pmi(struct kvm_vcpu *vcpu)
{
- u64 data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+ u64 data = vmx_guest_debugctl_read();
if (data & DEBUGCTLMSR_FREEZE_LBRS_ON_PMI) {
data &= ~DEBUGCTLMSR_LBR;
- vmcs_write64(GUEST_IA32_DEBUGCTL, data);
+ vmx_guest_debugctl_write(vcpu, data);
}
}
@@ -679,7 +679,7 @@ void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
if (!lbr_desc->event) {
vmx_disable_lbr_msrs_passthrough(vcpu);
- if (vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR)
+ if (vmx_guest_debugctl_read() & DEBUGCTLMSR_LBR)
goto warn;
if (test_bit(INTEL_PMC_IDX_FIXED_VLBR, pmu->pmc_in_use))
goto warn;
@@ -701,7 +701,7 @@ void vmx_passthrough_lbr_msrs(struct kvm_vcpu *vcpu)
static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
{
- if (!(vmcs_read64(GUEST_IA32_DEBUGCTL) & DEBUGCTLMSR_LBR))
+ if (!(vmx_guest_debugctl_read() & DEBUGCTLMSR_LBR))
intel_pmu_release_guest_lbr_event(vcpu);
}
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 50d45c18fce9..4bb25519e7ce 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2148,7 +2148,7 @@ int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = vmx->pt_desc.guest.addr_a[index / 2];
break;
case MSR_IA32_DEBUGCTLMSR:
- msr_info->data = vmcs_read64(GUEST_IA32_DEBUGCTL);
+ msr_info->data = vmx_guest_debugctl_read();
break;
default:
find_uret_msr:
@@ -2282,7 +2282,8 @@ int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
VM_EXIT_SAVE_DEBUG_CONTROLS)
get_vmcs12(vcpu)->guest_ia32_debugctl = data;
- vmcs_write64(GUEST_IA32_DEBUGCTL, data);
+ vmx_guest_debugctl_write(vcpu, data);
+
if (intel_pmu_lbr_is_enabled(vcpu) && !to_vmx(vcpu)->lbr_desc.event &&
(data & DEBUGCTLMSR_LBR))
intel_pmu_create_guest_lbr_event(vcpu);
@@ -4831,7 +4832,8 @@ static void init_vmcs(struct vcpu_vmx *vmx)
vmcs_write32(GUEST_SYSENTER_CS, 0);
vmcs_writel(GUEST_SYSENTER_ESP, 0);
vmcs_writel(GUEST_SYSENTER_EIP, 0);
- vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
+
+ vmx_guest_debugctl_write(&vmx->vcpu, 0);
if (cpu_has_vmx_tpr_shadow()) {
vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, 0);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index ee330d14089d..5b2c5cb5e32e 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -438,6 +438,16 @@ void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu);
u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated);
bool vmx_is_valid_debugctl(struct kvm_vcpu *vcpu, u64 data, bool host_initiated);
+static inline void vmx_guest_debugctl_write(struct kvm_vcpu *vcpu, u64 val)
+{
+ vmcs_write64(GUEST_IA32_DEBUGCTL, val);
+}
+
+static inline u64 vmx_guest_debugctl_read(void)
+{
+ return vmcs_read64(GUEST_IA32_DEBUGCTL);
+}
+
/*
* Note, early Intel manuals have the write-low and read-high bitmap offsets
* the wrong way round. The bitmaps control MSRs 0x00000000-0x00001fff and
--
2.51.0.rc1.163.g2494970778-goog
next prev parent reply other threads:[~2025-08-15 0:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-15 0:57 [PATCH 6.12.y 0/7] KVM: x86: Backports for 6.12.y Sean Christopherson
2025-08-15 0:57 ` [PATCH 6.12.y 1/7] KVM: x86: Convert vcpu_run()'s immediate exit param into a generic bitmap Sean Christopherson
2025-08-15 0:57 ` [PATCH 6.12.y 2/7] KVM: x86: Drop kvm_x86_ops.set_dr6() in favor of a new KVM_RUN flag Sean Christopherson
2025-08-15 0:57 ` [PATCH 6.12.y 3/7] KVM: VMX: Allow guest to set DEBUGCTL.RTM_DEBUG if RTM is supported Sean Christopherson
2025-08-15 0:57 ` [PATCH 6.12.y 4/7] KVM: VMX: Extract checking of guest's DEBUGCTL into helper Sean Christopherson
2025-08-15 0:57 ` [PATCH 6.12.y 5/7] KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter Sean Christopherson
2025-08-15 0:57 ` Sean Christopherson [this message]
2025-08-15 0:57 ` [PATCH 6.12.y 7/7] KVM: VMX: Preserve host's DEBUGCTLMSR_FREEZE_IN_SMM while running the guest Sean Christopherson
2025-08-17 0:51 ` [PATCH 6.12.y 0/7] KVM: x86: Backports for 6.12.y Sasha Levin
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