From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nadav Har'El" Subject: [PATCH 14/31] nVMX: Implement VMREAD and VMWRITE Date: Mon, 16 May 2011 22:51:05 +0300 Message-ID: <201105161951.p4GJp5Hb001811@rice.haifa.ibm.com> References: <1305575004-nyh@il.ibm.com> Cc: gleb@redhat.com, avi@redhat.com To: kvm@vger.kernel.org Return-path: Received: from mtagate3.uk.ibm.com ([194.196.100.163]:34620 "EHLO mtagate3.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751216Ab1EPTvI (ORCPT ); Mon, 16 May 2011 15:51:08 -0400 Received: from d06nrmr1307.portsmouth.uk.ibm.com (d06nrmr1307.portsmouth.uk.ibm.com [9.149.38.129]) by mtagate3.uk.ibm.com (8.13.1/8.13.1) with ESMTP id p4GJp7Eh024357 for ; Mon, 16 May 2011 19:51:07 GMT Received: from d06av07.portsmouth.uk.ibm.com (d06av07.portsmouth.uk.ibm.com [9.149.37.248]) by d06nrmr1307.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p4GJp7IW2379952 for ; Mon, 16 May 2011 20:51:07 +0100 Received: from d06av07.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av07.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p4GJp7Pi019560 for ; Mon, 16 May 2011 13:51:07 -0600 Sender: kvm-owner@vger.kernel.org List-ID: Implement the VMREAD and VMWRITE instructions. With these instructions, L1 can read and write to the VMCS it is holding. The values are read or written to the fields of the vmcs12 structure introduced in a previous patch. Signed-off-by: Nadav Har'El --- arch/x86/kvm/vmx.c | 176 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 174 insertions(+), 2 deletions(-) --- .before/arch/x86/kvm/vmx.c 2011-05-16 22:36:48.000000000 +0300 +++ .after/arch/x86/kvm/vmx.c 2011-05-16 22:36:48.000000000 +0300 @@ -4893,6 +4893,178 @@ static int handle_vmclear(struct kvm_vcp return 1; } +enum vmcs_field_type { + VMCS_FIELD_TYPE_U16 = 0, + VMCS_FIELD_TYPE_U64 = 1, + VMCS_FIELD_TYPE_U32 = 2, + VMCS_FIELD_TYPE_NATURAL_WIDTH = 3 +}; + +static inline int vmcs_field_type(unsigned long field) +{ + if (0x1 & field) /* the *_HIGH fields are all 32 bit */ + return VMCS_FIELD_TYPE_U32; + return (field >> 13) & 0x3 ; +} + +static inline int vmcs_field_readonly(unsigned long field) +{ + return (((field >> 10) & 0x3) == 1); +} + +/* + * Read a vmcs12 field. Since these can have varying lengths and we return + * one type, we chose the biggest type (u64) and zero-extend the return value + * to that size. Note that the caller, handle_vmread, might need to use only + * some of the bits we return here (e.g., on 32-bit guests, only 32 bits of + * 64-bit fields are to be returned). + */ +static inline bool vmcs12_read_any(struct kvm_vcpu *vcpu, + unsigned long field, u64 *ret) +{ + short offset = vmcs_field_to_offset(field); + char *p; + + if (offset < 0) + return 0; + + p = ((char *)(get_vmcs12(vcpu))) + offset; + + switch (vmcs_field_type(field)) { + case VMCS_FIELD_TYPE_NATURAL_WIDTH: + *ret = *((natural_width *)p); + return 1; + case VMCS_FIELD_TYPE_U16: + *ret = *((u16 *)p); + return 1; + case VMCS_FIELD_TYPE_U32: + *ret = *((u32 *)p); + return 1; + case VMCS_FIELD_TYPE_U64: + *ret = *((u64 *)p); + return 1; + default: + return 0; /* can never happen. */ + } +} + +static int handle_vmread(struct kvm_vcpu *vcpu) +{ + unsigned long field; + u64 field_value; + unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION); + u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO); + gva_t gva = 0; + + if (!nested_vmx_check_permission(vcpu)) + return 1; + + /* Decode instruction info and find the field to read */ + field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf)); + /* Read the field, zero-extended to a u64 field_value */ + if (!vmcs12_read_any(vcpu, field, &field_value)) { + nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT); + skip_emulated_instruction(vcpu); + return 1; + } + /* + * Now copy part of this value to register or memory, as requested. + * Note that the number of bits actually copied is 32 or 64 depending + * on the guest's mode (32 or 64 bit), not on the given field's length. + */ + if (vmx_instruction_info & (1u << 10)) { + kvm_register_write(vcpu, (((vmx_instruction_info) >> 3) & 0xf), + field_value); + } else { + if (get_vmx_mem_address(vcpu, exit_qualification, + vmx_instruction_info, &gva)) + return 1; + /* _system ok, as nested_vmx_check_permission verified cpl=0 */ + kvm_write_guest_virt_system(&vcpu->arch.emulate_ctxt, gva, + &field_value, (is_long_mode(vcpu) ? 8 : 4), NULL); + } + + nested_vmx_succeed(vcpu); + skip_emulated_instruction(vcpu); + return 1; +} + + +static int handle_vmwrite(struct kvm_vcpu *vcpu) +{ + unsigned long field; + gva_t gva; + unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION); + u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO); + char *p; + short offset; + /* The value to write might be 32 or 64 bits, depending on L1's long + * mode, and eventually we need to write that into a field of several + * possible lengths. The code below first zero-extends the value to 64 + * bit (field_value), and then copies only the approriate number of + * bits into the vmcs12 field. + */ + u64 field_value = 0; + struct x86_exception e; + + if (!nested_vmx_check_permission(vcpu)) + return 1; + + if (vmx_instruction_info & (1u << 10)) + field_value = kvm_register_read(vcpu, + (((vmx_instruction_info) >> 3) & 0xf)); + else { + if (get_vmx_mem_address(vcpu, exit_qualification, + vmx_instruction_info, &gva)) + return 1; + if (kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, gva, + &field_value, (is_long_mode(vcpu) ? 8 : 4), &e)) { + kvm_inject_page_fault(vcpu, &e); + return 1; + } + } + + + field = kvm_register_read(vcpu, (((vmx_instruction_info) >> 28) & 0xf)); + if (vmcs_field_readonly(field)) { + nested_vmx_failValid(vcpu, + VMXERR_VMWRITE_READ_ONLY_VMCS_COMPONENT); + skip_emulated_instruction(vcpu); + return 1; + } + + offset = vmcs_field_to_offset(field); + if (offset < 0) { + nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT); + skip_emulated_instruction(vcpu); + return 1; + } + p = ((char *) get_vmcs12(vcpu)) + offset; + + switch (vmcs_field_type(field)) { + case VMCS_FIELD_TYPE_U16: + *(u16 *)p = field_value; + break; + case VMCS_FIELD_TYPE_U32: + *(u32 *)p = field_value; + break; + case VMCS_FIELD_TYPE_U64: + *(u64 *)p = field_value; + break; + case VMCS_FIELD_TYPE_NATURAL_WIDTH: + *(natural_width *)p = field_value; + break; + default: + nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT); + skip_emulated_instruction(vcpu); + return 1; + } + + nested_vmx_succeed(vcpu); + skip_emulated_instruction(vcpu); + return 1; +} + /* Emulate the VMPTRLD instruction */ static int handle_vmptrld(struct kvm_vcpu *vcpu) { @@ -5004,9 +5176,9 @@ static int (*kvm_vmx_exit_handlers[])(st [EXIT_REASON_VMLAUNCH] = handle_vmx_insn, [EXIT_REASON_VMPTRLD] = handle_vmptrld, [EXIT_REASON_VMPTRST] = handle_vmptrst, - [EXIT_REASON_VMREAD] = handle_vmx_insn, + [EXIT_REASON_VMREAD] = handle_vmread, [EXIT_REASON_VMRESUME] = handle_vmx_insn, - [EXIT_REASON_VMWRITE] = handle_vmx_insn, + [EXIT_REASON_VMWRITE] = handle_vmwrite, [EXIT_REASON_VMOFF] = handle_vmoff, [EXIT_REASON_VMON] = handle_vmon, [EXIT_REASON_TPR_BELOW_THRESHOLD] = handle_tpr_below_threshold,