diff options
| -rw-r--r-- | executor/common_kvm_amd64_syzos.h | 18 | ||||
| -rw-r--r-- | executor/kvm.h | 1 | ||||
| -rw-r--r-- | sys/linux/test/amd64-syz_kvm_nested_vmresume-rdtsc | 27 |
3 files changed, 43 insertions, 3 deletions
diff --git a/executor/common_kvm_amd64_syzos.h b/executor/common_kvm_amd64_syzos.h index 96ff67897..9971c1c7b 100644 --- a/executor/common_kvm_amd64_syzos.h +++ b/executor/common_kvm_amd64_syzos.h @@ -686,7 +686,10 @@ GUEST_CODE static noinline void init_vmcs_control_fields(uint64 cpu_id, uint64 v // Read and write Primary Processor-Based controls from TRUE MSR. // We also add the bit to enable the secondary controls. vmx_msr = rdmsr(X86_MSR_IA32_VMX_TRUE_PROCBASED_CTLS); - vmwrite(VMCS_CPU_BASED_VM_EXEC_CONTROL, (uint32)vmx_msr | CPU_BASED_ACTIVATE_SECONDARY_CONTROLS | CPU_BASED_HLT_EXITING); + vmx_msr |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS; + // Exit on HLT and RDTSC. + vmx_msr |= CPU_BASED_HLT_EXITING | CPU_BASED_RDTSC_EXITING; + vmwrite(VMCS_CPU_BASED_VM_EXEC_CONTROL, (uint32)vmx_msr); // Set up VM-Exit controls via TRUE MSR: indicate a 64-bit host. vmx_msr = rdmsr(X86_MSR_IA32_VMX_TRUE_EXIT_CTLS); @@ -740,6 +743,7 @@ typedef enum { SYZOS_NESTED_EXIT_REASON_HLT = 1, SYZOS_NESTED_EXIT_REASON_INVD = 2, SYZOS_NESTED_EXIT_REASON_CPUID = 3, + SYZOS_NESTED_EXIT_REASON_RDTSC = 4, SYZOS_NESTED_EXIT_REASON_UNKNOWN = 0xFF, } syz_nested_exit_reason; @@ -758,6 +762,7 @@ GUEST_CODE static void guest_uexit_l2(uint64 exit_reason, syz_nested_exit_reason #define EXIT_REASON_CPUID 0xa #define EXIT_REASON_HLT 0xc #define EXIT_REASON_INVD 0xd +#define EXIT_REASON_RDTSC 0x10 GUEST_CODE static syz_nested_exit_reason map_intel_exit_reason(uint64 basic_reason) { @@ -769,6 +774,8 @@ GUEST_CODE static syz_nested_exit_reason map_intel_exit_reason(uint64 basic_reas return SYZOS_NESTED_EXIT_REASON_INVD; if (reason == EXIT_REASON_CPUID) return SYZOS_NESTED_EXIT_REASON_CPUID; + if (reason == EXIT_REASON_RDTSC) + return SYZOS_NESTED_EXIT_REASON_RDTSC; return SYZOS_NESTED_EXIT_REASON_UNKNOWN; } @@ -777,7 +784,8 @@ GUEST_CODE static void advance_l2_rip_intel(uint64 basic_reason) // Disable optimizations. volatile uint64 reason = basic_reason; uint64 rip = vmread(VMCS_GUEST_RIP); - if ((reason == EXIT_REASON_INVD) || (reason == EXIT_REASON_CPUID)) + if ((reason == EXIT_REASON_INVD) || (reason == EXIT_REASON_CPUID) || + (reason == EXIT_REASON_RDTSC)) rip += 2; vmwrite(VMCS_GUEST_RIP, rip); } @@ -837,6 +845,7 @@ __attribute__((naked)) GUEST_CODE static void nested_vm_exit_handler_intel_asm(v [vm_exit_reason] "i"(VMCS_VM_EXIT_REASON) : "memory", "cc", "rbx", "rdi", "rsi"); } +#define VMEXIT_RDTSC 0x6e #define VMEXIT_CPUID 0x72 #define VMEXIT_INVD 0x76 #define VMEXIT_HLT 0x78 @@ -851,6 +860,8 @@ GUEST_CODE static syz_nested_exit_reason map_amd_exit_reason(uint64 basic_reason return SYZOS_NESTED_EXIT_REASON_INVD; if (reason == VMEXIT_CPUID) return SYZOS_NESTED_EXIT_REASON_CPUID; + if (reason == VMEXIT_RDTSC) + return SYZOS_NESTED_EXIT_REASON_RDTSC; return SYZOS_NESTED_EXIT_REASON_UNKNOWN; } @@ -860,7 +871,8 @@ GUEST_CODE static void advance_l2_rip_amd(uint64 basic_reason, uint64 cpu_id, ui volatile uint64 reason = basic_reason; uint64 vmcb_addr = X86_SYZOS_ADDR_VMCS_VMCB(cpu_id, vm_id); uint64 rip = vmcb_read64((volatile uint8*)vmcb_addr, VMCB_GUEST_RIP); - if ((reason == VMEXIT_INVD) || (reason == VMEXIT_CPUID)) + if ((reason == VMEXIT_INVD) || (reason == VMEXIT_CPUID) || + (reason == VMEXIT_RDTSC)) rip += 2; vmcb_write64(vmcb_addr, VMCB_GUEST_RIP, rip); } diff --git a/executor/kvm.h b/executor/kvm.h index d7c708b34..7d6718aa9 100644 --- a/executor/kvm.h +++ b/executor/kvm.h @@ -244,6 +244,7 @@ // VMX control bits #define RFLAGS_1_BIT (1ULL << 1) #define CPU_BASED_HLT_EXITING (1U << 7) +#define CPU_BASED_RDTSC_EXITING (1U << 12) #define AR_TSS_AVAILABLE 0x0089 #define SVM_ATTR_LDTR_UNUSABLE 0x0000 #define VMX_AR_TSS_BUSY 0x008b diff --git a/sys/linux/test/amd64-syz_kvm_nested_vmresume-rdtsc b/sys/linux/test/amd64-syz_kvm_nested_vmresume-rdtsc new file mode 100644 index 000000000..3c0e25635 --- /dev/null +++ b/sys/linux/test/amd64-syz_kvm_nested_vmresume-rdtsc @@ -0,0 +1,27 @@ +# +# requires: arch=amd64 -threaded +# +r0 = openat$kvm(0, &AUTO='/dev/kvm\x00', 0x0, 0x0) +r1 = ioctl$KVM_CREATE_VM(r0, AUTO, 0x0) +r2 = syz_kvm_setup_syzos_vm$x86(r1, &(0x7f0000c00000/0x400000)=nil) + +# Create a nested VM that performs RDTSC (0f 31) and HLT (f4). +# +r3 = syz_kvm_add_vcpu$x86(r2, &AUTO={0x0, &AUTO=[@enable_nested={AUTO, AUTO, 0x0}, @nested_create_vm={AUTO, AUTO, 0x0}, @nested_load_code={AUTO, AUTO, {0x0, "0f31f4"}}, @nested_vmlaunch={AUTO, AUTO, 0x0}, @nested_vmresume={AUTO, AUTO, 0x0}], AUTO}) +r4 = ioctl$KVM_GET_VCPU_MMAP_SIZE(r0, AUTO) +r5 = mmap$KVM_VCPU(&(0x7f0000009000/0x1000)=nil, r4, 0x3, 0x1, r3, 0x0) + +# L2 VM executes CPUID. Exit reason is mapped to 0xe2e20004. +# +ioctl$KVM_RUN(r3, AUTO, 0x0) +syz_kvm_assert_syzos_uexit$x86(r5, 0xe2e20004) + +# L1 resumes L2, which executes HLT. Exit reason is mapped to 0xe2e20001. +# +ioctl$KVM_RUN(r3, AUTO, 0x0) +syz_kvm_assert_syzos_uexit$x86(r5, 0xe2e20001) + +# guest_main should finish with guest_uexit(-1). +# +ioctl$KVM_RUN(r3, AUTO, 0x0) +syz_kvm_assert_syzos_uexit$x86(r5, 0xffffffff) |