diff options
Diffstat (limited to 'arch/x86/kvm/vmx.c')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 487952b..74afd86 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4343,6 +4343,59 @@ static int handle_vmoff(struct kvm_vcpu *vcpu) } /* + * Decode the memory-address operand of a vmx instruction, as recorded on an + * exit caused by such an instruction (run by a guest hypervisor). + * On success, returns 0. When the operand is invalid, returns 1 and throws + * #UD or #GP. + */ +static int get_vmx_mem_address(struct kvm_vcpu *vcpu, + unsigned long exit_qualification, + u32 vmx_instruction_info, gva_t *ret) +{ + /* + * According to Vol. 3B, "Information for VM Exits Due to Instruction + * Execution", on an exit, vmx_instruction_info holds most of the + * addressing components of the operand. Only the displacement part + * is put in exit_qualification (see 3B, "Basic VM-Exit Information"). + * For how an actual address is calculated from all these components, + * refer to Vol. 1, "Operand Addressing". + */ + int scaling = vmx_instruction_info & 3; + int addr_size = (vmx_instruction_info >> 7) & 7; + bool is_reg = vmx_instruction_info & (1u << 10); + int seg_reg = (vmx_instruction_info >> 15) & 7; + int index_reg = (vmx_instruction_info >> 18) & 0xf; + bool index_is_valid = !(vmx_instruction_info & (1u << 22)); + int base_reg = (vmx_instruction_info >> 23) & 0xf; + bool base_is_valid = !(vmx_instruction_info & (1u << 27)); + + if (is_reg) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + /* Addr = segment_base + offset */ + /* offset = base + [index * scale] + displacement */ + *ret = vmx_get_segment_base(vcpu, seg_reg); + if (base_is_valid) + *ret += kvm_register_read(vcpu, base_reg); + if (index_is_valid) + *ret += kvm_register_read(vcpu, index_reg)<<scaling; + *ret += exit_qualification; /* holds the displacement */ + + if (addr_size == 1) /* 32 bit */ + *ret &= 0xffffffff; + + /* + * TODO: throw #GP (and return 1) in various cases that the VM* + * instructions require it - e.g., offset beyond segment limit, + * unusable or unreadable/unwritable segment, non-canonical 64-bit + * address, and so on. Currently these are not checked. + */ + return 0; +} + +/* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs * to be done to userspace and return 0. |
