Date: Fri, 22 May 2015 17:34:23 +0000 (UTC) From: Neel Natu <neel@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r283293 - in head/sys/amd64/vmm: . intel Message-ID: <201505221734.t4MHYNam053647@svn.freebsd.org>
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Author: neel Date: Fri May 22 17:34:22 2015 New Revision: 283293 URL: https://svnweb.freebsd.org/changeset/base/283293 Log: Don't rely on the 'VM-exit instruction length' field in the VMCS to always have an accurate length on an EPT violation. This is not needed by the instruction decoding code because it also has to work with AMD/SVM that does not provide a valid instruction length on a Nested Page Fault. In collaboration with: Leon Dang (ldang@nahannisys.com) Discussed with: grehan MFC after: 1 week Modified: head/sys/amd64/vmm/intel/vmx.c head/sys/amd64/vmm/vmm.c Modified: head/sys/amd64/vmm/intel/vmx.c ============================================================================== --- head/sys/amd64/vmm/intel/vmx.c Fri May 22 17:06:33 2015 (r283292) +++ head/sys/amd64/vmm/intel/vmx.c Fri May 22 17:34:22 2015 (r283293) @@ -1780,6 +1780,7 @@ vmexit_inst_emul(struct vm_exit *vmexit, paging = &vmexit->u.inst_emul.paging; vmexit->exitcode = VM_EXITCODE_INST_EMUL; + vmexit->inst_length = 0; vmexit->u.inst_emul.gpa = gpa; vmexit->u.inst_emul.gla = gla; vmx_paging_info(paging); Modified: head/sys/amd64/vmm/vmm.c ============================================================================== --- head/sys/amd64/vmm/vmm.c Fri May 22 17:06:33 2015 (r283292) +++ head/sys/amd64/vmm/vmm.c Fri May 22 17:34:22 2015 (r283293) @@ -1256,11 +1256,14 @@ vm_handle_inst_emul(struct vm *vm, int v mem_region_read_t mread; mem_region_write_t mwrite; enum vm_cpu_mode cpu_mode; - int cs_d, error, fault, length; + int cs_d, error, fault; vcpu = &vm->vcpu[vcpuid]; vme = &vcpu->exitinfo; + KASSERT(vme->inst_length == 0, ("%s: invalid inst_length %d", + __func__, vme->inst_length)); + gla = vme->u.inst_emul.gla; gpa = vme->u.inst_emul.gpa; cs_base = vme->u.inst_emul.cs_base; @@ -1273,13 +1276,8 @@ vm_handle_inst_emul(struct vm *vm, int v /* Fetch, decode and emulate the faulting instruction */ if (vie->num_valid == 0) { - /* - * If the instruction length is not known then assume a - * maximum size instruction. - */ - length = vme->inst_length ? vme->inst_length : VIE_INST_SIZE; error = vmm_fetch_instruction(vm, vcpuid, paging, vme->rip + - cs_base, length, vie, &fault); + cs_base, VIE_INST_SIZE, vie, &fault); } else { /* * The instruction bytes have already been copied into 'vie' @@ -1297,13 +1295,12 @@ vm_handle_inst_emul(struct vm *vm, int v } /* - * If the instruction length was not specified then update it now - * along with 'nextrip'. + * Update 'nextrip' based on the length of the emulated instruction. */ - if (vme->inst_length == 0) { - vme->inst_length = vie->num_processed; - vcpu->nextrip += vie->num_processed; - } + vme->inst_length = vie->num_processed; + vcpu->nextrip += vie->num_processed; + VCPU_CTR1(vm, vcpuid, "nextrip updated to %#lx after instruction " + "decoding", vcpu->nextrip); /* return to userland unless this is an in-kernel emulated device */ if (gpa >= DEFAULT_APIC_BASE && gpa < DEFAULT_APIC_BASE + PAGE_SIZE) {
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