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 v7 19/21] KVM: nVMX: Add FRED-related VMCS field checks
Date: Fri, 29 Aug 2025 08:31:47 -0700 [thread overview]
Message-ID: <20250829153149.2871901-20-xin@zytor.com> (raw)
In-Reply-To: <20250829153149.2871901-1-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 | 117 +++++++++++++++++++++++++++++++++-----
1 file changed, 104 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0cb9a2e43ad2..b56bbac36749 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3031,6 +3031,8 @@ 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,
@@ -3048,22 +3050,11 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
u8 vector = intr_info & INTR_INFO_VECTOR_MASK;
u32 intr_type = intr_info & INTR_INFO_INTR_TYPE_MASK;
bool has_error_code = intr_info & INTR_INFO_DELIVER_CODE_MASK;
+ 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;
- /* VM-entry interruption-info field: interruption type */
- if (CC(intr_type == INTR_TYPE_RESERVED) ||
- CC(intr_type == INTR_TYPE_OTHER_EVENT &&
- !nested_cpu_supports_monitor_trap_flag(vcpu)))
- return -EINVAL;
-
- /* 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))
- return -EINVAL;
-
/*
* Cannot deliver error code in real mode or if the interrupt
* type is not hardware exception. For other cases, do the
@@ -3088,8 +3079,28 @@ static int nested_check_vm_entry_controls(struct kvm_vcpu *vcpu,
if (CC(intr_info & INTR_INFO_RESVD_BITS_MASK))
return -EINVAL;
- /* VM-entry instruction length */
+ /*
+ * 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_type == INTR_TYPE_HARD_EXCEPTION) &&
+ intr_info & INTR_INFO_NESTED_EXCEPTION_MASK))
+ return -EINVAL;
+
switch (intr_type) {
+ case INTR_TYPE_EXT_INTR:
+ break;
+ case INTR_TYPE_RESERVED:
+ return -EINVAL;
+ case INTR_TYPE_NMI_INTR:
+ if (CC(vector != NMI_VECTOR))
+ return -EINVAL;
+ break;
+ case INTR_TYPE_HARD_EXCEPTION:
+ if (CC(vector > 31))
+ return -EINVAL;
+ break;
case INTR_TYPE_SOFT_EXCEPTION:
case INTR_TYPE_SOFT_INTR:
case INTR_TYPE_PRIV_SW_EXCEPTION:
@@ -3097,6 +3108,24 @@ 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:
+ switch (vector) {
+ case 0:
+ if (CC(!nested_cpu_supports_monitor_trap_flag(vcpu)))
+ return -EINVAL;
+ break;
+ case 1:
+ case 2:
+ if (CC(!fred_enabled))
+ return -EINVAL;
+ if (CC(vmcs12->vm_entry_instruction_len > X86_MAX_INSTRUCTION_LENGTH))
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+ break;
}
}
@@ -3184,9 +3213,29 @@ 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) {
+ 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;
}
@@ -3354,6 +3403,48 @@ 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) {
+ 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);
+ switch (ss_dpl) {
+ case 0:
+ if (CC(!(vmcs12->guest_cs_ar_bytes & VMX_AR_L_MASK)))
+ return -EINVAL;
+ break;
+ case 1:
+ case 2:
+ return -EINVAL;
+ case 3:
+ if (CC(vmcs12->guest_rflags & X86_EFLAGS_IOPL))
+ return -EINVAL;
+ if (CC(vmcs12->guest_interruptibility_info & GUEST_INTR_STATE_STI))
+ return -EINVAL;
+ break;
+ }
+ }
+ } else {
+ if (CC(vmcs12->guest_cr4 & X86_CR4_FRED))
+ return -EINVAL;
+ }
+
if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE) {
if (CC(!is_valid_cet_state(vcpu, vmcs12->guest_s_cet, vmcs12->guest_ssp,
vmcs12->guest_ssp_tbl)))
--
2.51.0
next prev parent reply other threads:[~2025-08-29 15:33 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-29 15:31 [PATCH v7 00/21] Enable FRED with KVM VMX Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 01/21] KVM: VMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 02/21] KVM: VMX: Initialize VM entry/exit FRED controls in vmcs_config Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 03/21] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 04/21] x86/cea: Prefix event stack names with ESTACK_ Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 05/21] x86/cea: Export API for per-CPU exception stacks for KVM Xin Li (Intel)
2025-08-29 16:52 ` Xin Li
2025-08-29 15:31 ` [PATCH v7 06/21] KVM: VMX: Initialize VMCS FRED fields Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 07/21] KVM: VMX: Set FRED MSR intercepts Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 08/21] KVM: VMX: Save/restore guest FRED RSP0 Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 09/21] KVM: VMX: Add support for saving and restoring FRED MSRs Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 10/21] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 11/21] KVM: VMX: Virtualize FRED event_data Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 12/21] KVM: VMX: Virtualize FRED nested exception tracking Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 13/21] KVM: x86: Save/restore the nested flag of an exception Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 14/21] KVM: x86: Mark CR4.FRED as not reserved Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 15/21] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 16/21] KVM: x86: Advertise support for FRED Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 17/21] KVM: nVMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 18/21] KVM: nVMX: Add FRED VMCS fields to nested VMX context handling Xin Li (Intel)
2025-08-29 15:31 ` Xin Li (Intel) [this message]
2025-08-29 15:31 ` [PATCH v7 20/21] KVM: nVMX: Add prerequisites to SHADOW_FIELD_R[OW] macros Xin Li (Intel)
2025-08-29 15:31 ` [PATCH v7 21/21] KVM: nVMX: Allow VMX FRED controls Xin Li (Intel)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250829153149.2871901-20-xin@zytor.com \
--to=xin@zytor.com \
--cc=andrew.cooper3@citrix.com \
--cc=bp@alien8.de \
--cc=chao.gao@intel.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@linux.intel.com \
--cc=hch@infradead.org \
--cc=hpa@zytor.com \
--cc=kvm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).