freebsd-nq/sys/amd64/vmm/amd/svm_support.S
Neel Natu 90e528f838 Restore the host's GS.base before returning from 'svm_launch()'.
Previously this was done by the caller of 'svm_launch()' after it returned.
This works fine as long as no code is executed in the interim that depends
on pcpu data.

The dtrace probe 'fbt:vmm:svm_launch:return' broke this assumption because
it calls 'dtrace_probe()' which in turn relies on pcpu data.

Reported by:	avg
MFC after:	1 week
2015-06-23 02:17:23 +00:00

133 lines
3.5 KiB
ArmAsm

/*-
* 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.
*
* $FreeBSD$
*/
#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
#define VMLOAD .byte 0x0f, 0x01, 0xda
#define VMRUN .byte 0x0f, 0x01, 0xd8
#define VMSAVE .byte 0x0f, 0x01, 0xdb
/*
* 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
VMRUN
VMSAVE
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)
/* 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, %ecx
wrmsr
VLEAVE
ret
END(svm_launch)