From: "Xin Li (Intel)" <xin@zytor.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-doc@vger.kernel.org
Cc: pbonzini@redhat.com, seanjc@google.com, corbet@lwn.net,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
xin@zytor.com, luto@kernel.org, peterz@infradead.org,
andrew.cooper3@citrix.com, chao.gao@intel.com, hch@infradead.org
Subject: [PATCH v5 21/23] KVM: nVMX: Add FRED-related VMCS field checks
Date: Wed, 23 Jul 2025 10:53:39 -0700 [thread overview]
Message-ID: <20250723175341.1284463-22-xin@zytor.com> (raw)
In-Reply-To: <20250723175341.1284463-1-xin@zytor.com>
From: Xin Li <xin3.li@intel.com>
As with real hardware, nested VMX validates various VMCS fields, including
control and guest/host state fields. This patch adds checks for FRED-related
VMCS fields to support nested FRED functionality.
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Tested-by: Xuelian Guo <xuelian.guo@intel.com>
---
Change in v5:
* Add TB from Xuelian Guo.
---
arch/x86/kvm/vmx/nested.c | 80 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 79 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 30d2de1243ef..d215e5ade5ef 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2966,6 +2966,8 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
struct vmcs12 *vmcs12)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
+ bool fred_enabled = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) &&
+ (vmcs12->guest_cr4 & X86_CR4_FRED);
if (CC(!vmx_control_verify(vmcs12->vm_entry_controls,
vmx->nested.msrs.entry_ctls_low,
@@ -2984,6 +2986,7 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
u32 intr_type = intr_info & INTR_INFO_INTR_TYPE_MASK;
bool has_error_code = intr_info & INTR_INFO_DELIVER_CODE_MASK;
bool should_have_error_code;
+ bool has_nested_exception = vmx->nested.msrs.basic & VMX_BASIC_NESTED_EXCEPTION;
bool urg = nested_cpu_has2(vmcs12,
SECONDARY_EXEC_UNRESTRICTED_GUEST);
bool prot_mode = !urg || vmcs12->guest_cr0 & X86_CR0_PE;
@@ -2997,7 +3000,9 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
/* VM-entry interruption-info field: vector */
if (CC(intr_type == INTR_TYPE_NMI_INTR && vector != NMI_VECTOR) ||
CC(intr_type == INTR_TYPE_HARD_EXCEPTION && vector > 31) ||
- CC(intr_type == INTR_TYPE_OTHER_EVENT && vector != 0))
+ CC(intr_type == INTR_TYPE_OTHER_EVENT &&
+ ((!fred_enabled && vector > 0) ||
+ (fred_enabled && vector > 2))))
return -EINVAL;
/* VM-entry interruption-info field: deliver error code */
@@ -3016,6 +3021,15 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
if (CC(intr_info & INTR_INFO_RESVD_BITS_MASK))
return -EINVAL;
+ /*
+ * When the CPU enumerates VMX nested-exception support, bit 13
+ * (set to indicate a nested exception) of the intr info field
+ * may have value 1. Otherwise bit 13 is reserved.
+ */
+ if (CC(!has_nested_exception &&
+ (intr_info & INTR_INFO_NESTED_EXCEPTION_MASK)))
+ return -EINVAL;
+
/* VM-entry instruction length */
switch (intr_type) {
case INTR_TYPE_SOFT_EXCEPTION:
@@ -3025,6 +3039,12 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
CC(vmcs12->vm_entry_instruction_len == 0 &&
CC(!nested_cpu_has_zero_length_injection(vcpu))))
return -EINVAL;
+ break;
+ case INTR_TYPE_OTHER_EVENT:
+ if (fred_enabled && (vector == 1 || vector == 2))
+ if (CC(vmcs12->vm_entry_instruction_len > 15))
+ return -EINVAL;
+ break;
}
}
@@ -3098,9 +3118,30 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
if (ia32e) {
if (CC(!(vmcs12->host_cr4 & X86_CR4_PAE)))
return -EINVAL;
+ if (vmcs12->vm_exit_controls & VM_EXIT_ACTIVATE_SECONDARY_CONTROLS &&
+ vmcs12->secondary_vm_exit_controls & SECONDARY_VM_EXIT_LOAD_IA32_FRED) {
+ /* Bit 11, bits 5:4, and bit 2 of the IA32_FRED_CONFIG must be zero */
+ if (CC(vmcs12->host_ia32_fred_config &
+ (BIT_ULL(11) | GENMASK_ULL(5, 4) | BIT_ULL(2))) ||
+ CC(vmcs12->host_ia32_fred_rsp1 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->host_ia32_fred_rsp2 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->host_ia32_fred_rsp3 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->host_ia32_fred_ssp1 & GENMASK_ULL(2, 0)) ||
+ CC(vmcs12->host_ia32_fred_ssp2 & GENMASK_ULL(2, 0)) ||
+ CC(vmcs12->host_ia32_fred_ssp3 & GENMASK_ULL(2, 0)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_config & PAGE_MASK, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_rsp1, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_rsp2, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_rsp3, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_ssp1, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_ssp2, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->host_ia32_fred_ssp3, vcpu)))
+ return -EINVAL;
+ }
} else {
if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
+ CC(vmcs12->host_cr4 & X86_CR4_FRED) ||
CC((vmcs12->host_rip) >> 32))
return -EINVAL;
}
@@ -3245,6 +3286,43 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
CC((vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD))))
return -EINVAL;
+ if (ia32e) {
+ if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_FRED) {
+ /* Bit 11, bits 5:4, and bit 2 of the IA32_FRED_CONFIG must be zero */
+ if (CC(vmcs12->guest_ia32_fred_config &
+ (BIT_ULL(11) | GENMASK_ULL(5, 4) | BIT_ULL(2))) ||
+ CC(vmcs12->guest_ia32_fred_rsp1 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->guest_ia32_fred_rsp2 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->guest_ia32_fred_rsp3 & GENMASK_ULL(5, 0)) ||
+ CC(vmcs12->guest_ia32_fred_ssp1 & GENMASK_ULL(2, 0)) ||
+ CC(vmcs12->guest_ia32_fred_ssp2 & GENMASK_ULL(2, 0)) ||
+ CC(vmcs12->guest_ia32_fred_ssp3 & GENMASK_ULL(2, 0)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_config & PAGE_MASK, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_rsp1, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_rsp2, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_rsp3, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_ssp1, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_ssp2, vcpu)) ||
+ CC(is_noncanonical_msr_address(vmcs12->guest_ia32_fred_ssp3, vcpu)))
+ return -EINVAL;
+ }
+ if (vmcs12->guest_cr4 & X86_CR4_FRED) {
+ unsigned int ss_dpl = VMX_AR_DPL(vmcs12->guest_ss_ar_bytes);
+ if (CC(ss_dpl == 1 || ss_dpl == 2))
+ return -EINVAL;
+ if (ss_dpl == 0 &&
+ CC(!(vmcs12->guest_cs_ar_bytes & VMX_AR_L_MASK)))
+ return -EINVAL;
+ if (ss_dpl == 3 &&
+ (CC(vmcs12->guest_rflags & X86_EFLAGS_IOPL) ||
+ CC(vmcs12->guest_interruptibility_info & GUEST_INTR_STATE_STI)))
+ return -EINVAL;
+ }
+ } else {
+ if (CC(vmcs12->guest_cr4 & X86_CR4_FRED))
+ return -EINVAL;
+ }
+
if (nested_check_guest_non_reg_state(vmcs12))
return -EINVAL;
--
2.50.1
next prev parent reply other threads:[~2025-07-23 17:54 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-23 17:53 [PATCH v5 00/23] Enable FRED with KVM VMX Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 01/23] KVM: VMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 02/23] KVM: VMX: Initialize VM entry/exit FRED controls in vmcs_config Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 03/23] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 04/23] x86/cea: Export an API to get per CPU exception stacks for KVM to use Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 05/23] KVM: VMX: Fix an indentation Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 06/23] KVM: VMX: Initialize VMCS FRED fields Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 07/23] KVM: VMX: Set FRED MSR intercepts Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 08/23] KVM: VMX: Save/restore guest FRED RSP0 Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 09/23] KVM: VMX: Add host MSR read/write helpers to streamline preemption logic Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 10/23] KVM: VMX: Add support for FRED context save/restore Xin Li (Intel)
2025-07-24 5:35 ` Chao Gao
2025-07-24 18:01 ` Xin Li
2025-08-02 17:15 ` [PATCH v5A " Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 11/23] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 12/23] KVM: VMX: Virtualize FRED event_data Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 13/23] KVM: VMX: Virtualize FRED nested exception tracking Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 14/23] Documentation: kvm: Fix a section number typo Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 15/23] KVM: x86: Save/restore the nested flag of an exception Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 16/23] KVM: x86: Mark CR4.FRED as not reserved Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 17/23] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 18/23] KVM: x86: Advertise support for FRED Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 19/23] KVM: nVMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 20/23] KVM: nVMX: Add FRED VMCS fields to nested VMX context handling Xin Li (Intel)
2025-07-24 6:50 ` Chao Gao
2025-07-31 7:24 ` Xin Li
2025-08-02 17:17 ` [PATCH v5A " Xin Li (Intel)
2025-08-02 17:33 ` Xin Li
2025-08-04 6:03 ` Xin Li
2025-07-23 17:53 ` Xin Li (Intel) [this message]
2025-07-23 17:53 ` [PATCH v5 22/23] KVM: nVMX: Allow VMX FRED controls Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 23/23] KVM: nVMX: Add prerequisites to SHADOW_FIELD_R[OW] macros Xin Li (Intel)
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