/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2011 NetApp, Inc.
* Copyright (c) 2013 Neel Natu <neel@freebsd.org>
* 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, 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 NETAPP, INC ``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 NETAPP, INC OR CONTRIBUTORS 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 <machine/specialreg.h>
#include "vmx_assym.h"
#ifdef SMP
#define LK lock ;
#else
#define LK
#endif
/* Be friendly to DTrace FBT's prologue/epilogue pattern matching */
#define VENTER push %rbp ; mov %rsp,%rbp
#define VLEAVE pop %rbp
/*
* Save the guest context.
*/
#define VMX_GUEST_SAVE \
movq %rdi,VMXCTX_GUEST_RDI(%rsp); \
movq %rsi,VMXCTX_GUEST_RSI(%rsp); \
movq %rdx,VMXCTX_GUEST_RDX(%rsp); \
movq %rcx,VMXCTX_GUEST_RCX(%rsp); \
movq %r8,VMXCTX_GUEST_R8(%rsp); \
movq %r9,VMXCTX_GUEST_R9(%rsp); \
movq %rax,VMXCTX_GUEST_RAX(%rsp); \
movq %rbx,VMXCTX_GUEST_RBX(%rsp); \
movq %rbp,VMXCTX_GUEST_RBP(%rsp); \
movq %r10,VMXCTX_GUEST_R10(%rsp); \
movq %r11,VMXCTX_GUEST_R11(%rsp); \
movq %r12,VMXCTX_GUEST_R12(%rsp); \
movq %r13,VMXCTX_GUEST_R13(%rsp); \
movq %r14,VMXCTX_GUEST_R14(%rsp); \
movq %r15,VMXCTX_GUEST_R15(%rsp); \
movq %cr2,%rdi; \
movq %rdi,VMXCTX_GUEST_CR2(%rsp); \
movq %rsp,%rdi;
/*
* Assumes that %rdi holds a pointer to the 'vmxctx'.
*
* On "return" all registers are updated to reflect guest state. The two
* exceptions are %rip and %rsp. These registers are atomically switched
* by hardware from the guest area of the vmcs.
*
* We modify %rsp to point to the 'vmxctx' so we can use it to restore
* host context in case of an error with 'vmlaunch' or 'vmresume'.
*/
#define VMX_GUEST_RESTORE \
movq %rdi,%rsp; \
movq VMXCTX_GUEST_CR2(%rdi),%rsi; \
movq %rsi,%cr2; \
movq VMXCTX_GUEST_RSI(%rdi),%rsi; \
movq VMXCTX_GUEST_RDX(%rdi),%rdx; \
movq VMXCTX_GUEST_RCX(%rdi),%rcx; \
movq VMXCTX_GUEST_R8(%rdi),%r8; \
movq VMXCTX_GUEST_R9(%rdi),%r9; \
movq VMXCTX_GUEST_RAX(%rdi),%rax; \
movq VMXCTX_GUEST_RBX(%rdi),%rbx; \
movq VMXCTX_GUEST_RBP(%rdi),%rbp; \
movq VMXCTX_GUEST_R10(%rdi),%r10; \
movq VMXCTX_GUEST_R11(%rdi),%r11; \
movq VMXCTX_GUEST_R12(%rdi),%r12; \
movq VMXCTX_GUEST_R13(%rdi),%r13; \
movq VMXCTX_GUEST_R14(%rdi),%r14; \
movq VMXCTX_GUEST_R15(%rdi),%r15; \
movq VMXCTX_GUEST_RDI(%rdi),%rdi; /* restore rdi the last */
/*
* Clobber the remaining registers with guest contents so they can't
* be misused.
*/
#define VMX_GUEST_CLOBBER \
xor %rax, %rax; \
xor %rcx, %rcx; \
xor %rdx, %rdx; \
xor %rsi, %rsi; \
xor %r8, %r8; \
xor %r9, %r9; \
xor %r10, %r10; \
xor %r11, %r11;
/*
* Save and restore the host context.
*
* Assumes that %rdi holds a pointer to the 'vmxctx'.
*/
#define VMX_HOST_SAVE \
movq %r15, VMXCTX_HOST_R15(%rdi); \
movq %r14, VMXCTX_HOST_R14(%rdi); \
movq %r13, VMXCTX_HOST_R13(%rdi); \
movq %r12, VMXCTX_HOST_R12(%rdi); \
movq %rbp, VMXCTX_HOST_RBP(%rdi); \
movq %rsp, VMXCTX_HOST_RSP(%rdi); \
movq %rbx, VMXCTX_HOST_RBX(%rdi); \
#define VMX_HOST_RESTORE \
movq VMXCTX_HOST_R15(%rdi), %r15; \
movq VMXCTX_HOST_R14(%rdi), %r14; \
movq VMXCTX_HOST_R13(%rdi), %r13; \
movq VMXCTX_HOST_R12(%rdi), %r12; \
movq VMXCTX_HOST_RBP(%rdi), %rbp; \
movq VMXCTX_HOST_RSP(%rdi), %rsp; \
movq VMXCTX_HOST_RBX(%rdi), %rbx; \
/*
* vmx_enter_guest(struct vmxctx *vmxctx, int launched)
* %rdi: pointer to the 'vmxctx'
* %rsi: pointer to the 'vmx'
* %edx: launch state of the VMCS
* Interrupts must be disabled on entry.
*/
ENTRY(vmx_enter_guest)
VENTER
/*
* Save host state before doing anything else.
*/
VMX_HOST_SAVE
guest_restore:
movl %edx, %r8d
cmpb $0, guest_l1d_flush_sw(%rip)
je after_l1d
call flush_l1d_sw
after_l1d:
cmpl $0, %r8d
je do_launch
VMX_GUEST_RESTORE
vmresume
/*
* In the common case 'vmresume' returns back to the host through
* 'vmx_exit_guest' with %rsp pointing to 'vmxctx'.
*
* If there is an error we return VMX_VMRESUME_ERROR to the caller.
*/
movq %rsp, %rdi /* point %rdi back to 'vmxctx' */
movl $VMX_VMRESUME_ERROR, %eax
jmp decode_inst_error
do_launch:
VMX_GUEST_RESTORE
vmlaunch
/*
* In the common case 'vmlaunch' returns back to the host through
* 'vmx_exit_guest' with %rsp pointing to 'vmxctx'.
*
* If there is an error we return VMX_VMLAUNCH_ERROR to the caller.
*/
movq %rsp, %rdi /* point %rdi back to 'vmxctx' */
movl $VMX_VMLAUNCH_ERROR, %eax
jmp decode_inst_error
decode_inst_error:
movl $VM_FAIL_VALID, %r11d
jz inst_error
movl $VM_FAIL_INVALID, %r11d
inst_error:
movl %r11d, VMXCTX_INST_FAIL_STATUS(%rdi)
/*
* The return value is already populated in %eax so we cannot use
* it as a scratch register beyond this point.
*/
VMX_HOST_RESTORE
VLEAVE
ret
/*
* Non-error VM-exit from the guest. Make this a label so it can
* be used by C code when setting up the VMCS.
* The VMCS-restored %rsp points to the struct vmxctx
*/
ALIGN_TEXT
.globl vmx_exit_guest_flush_rsb
vmx_exit_guest_flush_rsb:
/*
* Save guest state that is not automatically saved in the vmcs.
*/
VMX_GUEST_SAVE
VMX_HOST_RESTORE
VMX_GUEST_CLOBBER
/*
* 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
/*
* This will return to the caller of 'vmx_enter_guest()' with a return
* value of VMX_GUEST_VMEXIT.
*/
movl $VMX_GUEST_VMEXIT, %eax
VLEAVE
ret
.globl vmx_exit_guest
vmx_exit_guest:
/*
* Save guest state that is not automatically saved in the vmcs.
*/
VMX_GUEST_SAVE
VMX_HOST_RESTORE
VMX_GUEST_CLOBBER
/*
* This will return to the caller of 'vmx_enter_guest()' with a return
* value of VMX_GUEST_VMEXIT.
*/
movl $VMX_GUEST_VMEXIT, %eax
VLEAVE
ret
END(vmx_enter_guest)
/*
* %rdi = interrupt handler entry point
*
* Calling sequence described in the "Instruction Set Reference" for the "INT"
* instruction in Intel SDM, Vol 2.
*/
ENTRY(vmx_call_isr)
VENTER
mov %rsp, %r11 /* save %rsp */
and $~0xf, %rsp /* align on 16-byte boundary */
pushq $KERNEL_SS /* %ss */
pushq %r11 /* %rsp */
pushfq /* %rflags */
pushq $KERNEL_CS /* %cs */
cli /* disable interrupts */
callq *%rdi /* push %rip and call isr */
VLEAVE
ret
END(vmx_call_isr)