/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2013, Anish Gupta (akgupt3@gmail.com) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include <machine/asmacros.h> #include "svm_assym.h" /* * Be friendly to DTrace FBT's prologue/epilogue pattern matching. * * They are also responsible for saving/restoring the host %rbp across VMRUN. */ #define VENTER push %rbp ; mov %rsp,%rbp #define VLEAVE pop %rbp /* * svm_launch(uint64_t vmcb, struct svm_regctx *gctx, struct pcpu *pcpu) * %rdi: physical address of VMCB * %rsi: pointer to guest context * %rdx: pointer to the pcpu data */ ENTRY(svm_launch) VENTER /* save pointer to the pcpu data */ push %rdx /* * Host register state saved across a VMRUN. * * All "callee saved registers" except: * %rsp: because it is preserved by the processor across VMRUN. * %rbp: because it is saved/restored by the function prologue/epilogue. */ push %rbx push %r12 push %r13 push %r14 push %r15 /* Save the physical address of the VMCB in %rax */ movq %rdi, %rax push %rsi /* push guest context pointer on the stack */ /* * Restore guest state. */ movq SCTX_R8(%rsi), %r8 movq SCTX_R9(%rsi), %r9 movq SCTX_R10(%rsi), %r10 movq SCTX_R11(%rsi), %r11 movq SCTX_R12(%rsi), %r12 movq SCTX_R13(%rsi), %r13 movq SCTX_R14(%rsi), %r14 movq SCTX_R15(%rsi), %r15 movq SCTX_RBP(%rsi), %rbp movq SCTX_RBX(%rsi), %rbx movq SCTX_RCX(%rsi), %rcx movq SCTX_RDX(%rsi), %rdx movq SCTX_RDI(%rsi), %rdi movq SCTX_RSI(%rsi), %rsi /* %rsi must be restored last */ vmload %rax vmrun %rax vmsave %rax pop %rax /* pop guest context pointer from the stack */ /* * Save guest state. */ movq %r8, SCTX_R8(%rax) movq %r9, SCTX_R9(%rax) movq %r10, SCTX_R10(%rax) movq %r11, SCTX_R11(%rax) movq %r12, SCTX_R12(%rax) movq %r13, SCTX_R13(%rax) movq %r14, SCTX_R14(%rax) movq %r15, SCTX_R15(%rax) movq %rbp, SCTX_RBP(%rax) movq %rbx, SCTX_RBX(%rax) movq %rcx, SCTX_RCX(%rax) movq %rdx, SCTX_RDX(%rax) movq %rdi, SCTX_RDI(%rax) movq %rsi, SCTX_RSI(%rax) /* * To prevent malicious branch target predictions from * affecting the host, overwrite all entries in the RSB upon * exiting a guest. */ mov $16, %ecx /* 16 iterations, two calls per loop */ mov %rsp, %rax 0: call 2f /* create an RSB entry. */ 1: pause call 1b /* capture rogue speculation. */ 2: call 2f /* create an RSB entry. */ 1: pause call 1b /* capture rogue speculation. */ 2: sub $1, %ecx jnz 0b mov %rax, %rsp /* Restore host state */ pop %r15 pop %r14 pop %r13 pop %r12 pop %rbx /* Restore %GS.base to point to the host's pcpu data */ pop %rdx mov %edx, %eax shr $32, %rdx mov $MSR_GSBASE, %rcx wrmsr /* * Clobber the remaining registers with guest contents so they * can't be misused. */ xor %rbp, %rbp xor %rdi, %rdi xor %rsi, %rsi xor %r8, %r8 xor %r9, %r9 xor %r10, %r10 xor %r11, %r11 VLEAVE ret END(svm_launch)
