diff options
| author | Alexander Potapenko <glider@google.com> | 2025-11-20 10:57:11 +0100 |
|---|---|---|
| committer | Alexander Potapenko <glider@google.com> | 2025-11-21 08:57:45 +0000 |
| commit | 4b88ec680fc3ca03a90835040af2bee0bb6cadaf (patch) | |
| tree | b697ee45dd545e27c0116f5b1927de62fc961473 /executor | |
| parent | 280ea308c321115445df610f1a75b05bbadca5f3 (diff) | |
executor: sys/linux/test: basic CPUID handling in L2
Ensure L2 correctly exits to L1 on CPUID and resumes properly.
Add a test.
Diffstat (limited to 'executor')
| -rw-r--r-- | executor/common_kvm_amd64_syzos.h | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/executor/common_kvm_amd64_syzos.h b/executor/common_kvm_amd64_syzos.h index 27f4be400..96ff67897 100644 --- a/executor/common_kvm_amd64_syzos.h +++ b/executor/common_kvm_amd64_syzos.h @@ -739,6 +739,7 @@ GUEST_CODE static noinline void init_vmcs_control_fields(uint64 cpu_id, uint64 v typedef enum { SYZOS_NESTED_EXIT_REASON_HLT = 1, SYZOS_NESTED_EXIT_REASON_INVD = 2, + SYZOS_NESTED_EXIT_REASON_CPUID = 3, SYZOS_NESTED_EXIT_REASON_UNKNOWN = 0xFF, } syz_nested_exit_reason; @@ -754,6 +755,7 @@ 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 @@ -765,15 +767,19 @@ GUEST_CODE static syz_nested_exit_reason map_intel_exit_reason(uint64 basic_reas return SYZOS_NESTED_EXIT_REASON_HLT; if (reason == EXIT_REASON_INVD) return SYZOS_NESTED_EXIT_REASON_INVD; + if (reason == EXIT_REASON_CPUID) + return SYZOS_NESTED_EXIT_REASON_CPUID; return SYZOS_NESTED_EXIT_REASON_UNKNOWN; } GUEST_CODE static void advance_l2_rip_intel(uint64 basic_reason) { - if (basic_reason == EXIT_REASON_INVD) { - uint64 rip = vmread(VMCS_GUEST_RIP); - vmwrite(VMCS_GUEST_RIP, rip + 2); - } + // Disable optimizations. + volatile uint64 reason = basic_reason; + uint64 rip = vmread(VMCS_GUEST_RIP); + if ((reason == EXIT_REASON_INVD) || (reason == EXIT_REASON_CPUID)) + rip += 2; + vmwrite(VMCS_GUEST_RIP, rip); } // This function is called from inline assembly. @@ -831,6 +837,7 @@ __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_CPUID 0x72 #define VMEXIT_INVD 0x76 #define VMEXIT_HLT 0x78 @@ -842,16 +849,20 @@ GUEST_CODE static syz_nested_exit_reason map_amd_exit_reason(uint64 basic_reason return SYZOS_NESTED_EXIT_REASON_HLT; if (reason == VMEXIT_INVD) return SYZOS_NESTED_EXIT_REASON_INVD; + if (reason == VMEXIT_CPUID) + return SYZOS_NESTED_EXIT_REASON_CPUID; return SYZOS_NESTED_EXIT_REASON_UNKNOWN; } GUEST_CODE static void advance_l2_rip_amd(uint64 basic_reason, uint64 cpu_id, uint64 vm_id) { - if (basic_reason == VMEXIT_INVD) { - uint64 vmcb_addr = X86_SYZOS_ADDR_VMCS_VMCB(cpu_id, vm_id); - uint64 rip = vmcb_read64((volatile uint8*)vmcb_addr, VMCB_GUEST_RIP); - vmcb_write64(vmcb_addr, VMCB_GUEST_RIP, rip + 2); - } + // Disable optimizations. + 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)) + rip += 2; + vmcb_write64(vmcb_addr, VMCB_GUEST_RIP, rip); } __attribute__((used)) GUEST_CODE static void |