[PATCH v1 18/23] KVM: nVMX: Add VMCS FRED states checking

Xin Li
2023-11-08T19:00:32Z

Add FRED related VMCS fields checkings.

As real hardware, nested VMX performs checks on various VMCS fields,
including both controls and guest/host states. With the introduction
of VMX FRED, add FRED related VMCS fields checkings.

Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
arch/x86/kvm/vmx/nested.c | 70 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b85cd5c0ec98..bbfa09d575d3 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2940,6 +2940,7 @@ 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->guest_cr4 & X86_CR4_FRED);

if (CC(!vmx_control_verify(vmcs12->vm_entry_controls,
vmx->nested.msrs.entry_ctls_low,
@@ -2958,6 +2959,7 @@ 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;
@@ -2971,7 +2973,9 @@ 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 */
@@ -2990,6 +2994,15 @@ 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 the 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:
@@ -2999,6 +3012,12 @@ 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;
}
}

@@ -3056,14 +3075,31 @@ static int nested_vmx_check_host_state(struct kvm_vcpu *vcpu,
vmcs12->host_ia32_perf_global_ctrl)))
return -EINVAL;

+ /* Host FRED state checking */
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 2, bits 5:4, and bit 11 of the IA32_FRED_CONFIG must be zero */
+ if (CC(vmcs12->host_ia32_fred_config & 0x834) ||
+ CC(vmcs12->host_ia32_fred_rsp1 & 0x3F) ||
+ CC(vmcs12->host_ia32_fred_rsp2 & 0x3F) ||
+ CC(vmcs12->host_ia32_fred_rsp3 & 0x3F))
+ return -EINVAL;
+ if (CC(is_noncanonical_address(vmcs12->host_ia32_fred_config & ~0xFFFULL, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->host_ia32_fred_rsp1, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->host_ia32_fred_rsp2, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->host_ia32_fred_rsp3, vcpu)))
+ return -EINVAL;
+ }
} else {
if (CC(vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) ||
CC(vmcs12->host_cr4 & X86_CR4_PCIDE) ||
CC((vmcs12->host_rip) >> 32))
return -EINVAL;
+ if (CC(vmcs12->host_cr4 & X86_CR4_FRED))
+ return -EINVAL;
}

if (CC(vmcs12->host_cs_selector & (SEGMENT_RPL_MASK | SEGMENT_TI_MASK)) ||
@@ -3205,6 +3241,38 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
CC((vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD))))
return -EINVAL;

+ /* Guest FRED state checking */
+ if (ia32e) {
+ if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_FRED) {
+ /* Bit 2, bits 5:4, and bit 11 of the IA32_FRED_CONFIG must be zero */
+ if (CC(vmcs12->guest_ia32_fred_config & 0x834) ||
+ CC(vmcs12->guest_ia32_fred_rsp1 & 0x3F) ||
+ CC(vmcs12->guest_ia32_fred_rsp2 & 0x3F) ||
+ CC(vmcs12->guest_ia32_fred_rsp3 & 0x3F))
+ return -EINVAL;
+ if (CC(is_noncanonical_address(vmcs12->guest_ia32_fred_config & ~0xFFFULL, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->guest_ia32_fred_rsp1, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->guest_ia32_fred_rsp2, vcpu)) ||
+ CC(is_noncanonical_address(vmcs12->guest_ia32_fred_rsp3, 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;

--
2.42.0