/*-
* 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 <sys/cdefs.h>
#include "opt_bhyve_snapshot.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <machine/segments.h>
#include <machine/specialreg.h>
#include <machine/vmm.h>
#include <machine/vmm_snapshot.h>
#include "vmm_ktr.h"
#include "vmcb.h"
#include "svm.h"
#include "svm_softc.h"
/*
* The VMCB aka Virtual Machine Control Block is a 4KB aligned page
* in memory that describes the virtual machine.
*
* The VMCB contains:
* - instructions or events in the guest to intercept
* - control bits that modify execution environment of the guest
* - guest processor state (e.g. general purpose registers)
*/
/*
* Return VMCB segment area.
*/
static struct vmcb_segment *
vmcb_segptr(struct vmcb *vmcb, int type)
{
struct vmcb_state *state;
struct vmcb_segment *seg;
state = &vmcb->state;
switch (type) {
case VM_REG_GUEST_CS:
seg = &state->cs;
break;
case VM_REG_GUEST_DS:
seg = &state->ds;
break;
case VM_REG_GUEST_ES:
seg = &state->es;
break;
case VM_REG_GUEST_FS:
seg = &state->fs;
break;
case VM_REG_GUEST_GS:
seg = &state->gs;
break;
case VM_REG_GUEST_SS:
seg = &state->ss;
break;
case VM_REG_GUEST_GDTR:
seg = &state->gdt;
break;
case VM_REG_GUEST_IDTR:
seg = &state->idt;
break;
case VM_REG_GUEST_LDTR:
seg = &state->ldt;
break;
case VM_REG_GUEST_TR:
seg = &state->tr;
break;
default:
seg = NULL;
break;
}
return (seg);
}
static int
vmcb_access(struct svm_vcpu *vcpu, int write, int ident, uint64_t *val)
{
struct vmcb *vmcb;
int off, bytes;
char *ptr;
vmcb = svm_get_vmcb(vcpu);
off = VMCB_ACCESS_OFFSET(ident);
bytes = VMCB_ACCESS_BYTES(ident);
if ((off + bytes) >= sizeof (struct vmcb))
return (EINVAL);
ptr = (char *)vmcb;
if (!write)
*val = 0;
switch (bytes) {
case 8:
case 4:
case 2:
case 1:
if (write)
memcpy(ptr + off, val, bytes);
else
memcpy(val, ptr + off, bytes);
break;
default:
SVM_CTR1(vcpu, "Invalid size %d for VMCB access: %d", bytes);
return (EINVAL);
}
/* Invalidate all VMCB state cached by h/w. */
if (write)
svm_set_dirty(vcpu, 0xffffffff);
return (0);
}
/*
* Read from segment selector, control and general purpose register of VMCB.
*/
int
vmcb_read(struct svm_vcpu *vcpu, int ident, uint64_t *retval)
{
struct vmcb *vmcb;
struct vmcb_state *state;
struct vmcb_segment *seg;
int err;
vmcb = svm_get_vmcb(vcpu);
state = &vmcb->state;
err = 0;
if (VMCB_ACCESS_OK(ident))
return (vmcb_access(vcpu, 0, ident, retval));
switch (ident) {
case VM_REG_GUEST_CR0:
*retval = state->cr0;
break;
case VM_REG_GUEST_CR2:
*retval = state->cr2;
break;
case VM_REG_GUEST_CR3:
*retval = state->cr3;
break;
case VM_REG_GUEST_CR4:
*retval = state->cr4;
break;
case VM_REG_GUEST_DR6:
*retval = state->dr6;
break;
case VM_REG_GUEST_DR7:
*retval = state->dr7;
break;
case VM_REG_GUEST_EFER:
*retval = state->efer;
break;
case VM_REG_GUEST_RAX:
*retval = state->rax;
break;
case VM_REG_GUEST_RFLAGS:
*retval = state->rflags;
break;
case VM_REG_GUEST_RIP:
*retval = state->rip;
break;
case VM_REG_GUEST_RSP:
*retval = state->rsp;
break;
case VM_REG_GUEST_CS:
case VM_REG_GUEST_DS:
case VM_REG_GUEST_ES:
case VM_REG_GUEST_FS:
case VM_REG_GUEST_GS:
case VM_REG_GUEST_SS:
case VM_REG_GUEST_LDTR:
case VM_REG_GUEST_TR:
seg = vmcb_segptr(vmcb, ident);
KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
__func__, ident));
*retval = seg->selector;
break;
case VM_REG_GUEST_GDTR:
case VM_REG_GUEST_IDTR:
/* GDTR and IDTR don't have segment selectors */
err = EINVAL;
break;
default:
err = EINVAL;
break;
}
return (err);
}
/*
* Write to segment selector, control and general purpose register of VMCB.
*/
int
vmcb_write(struct svm_vcpu *vcpu, int ident, uint64_t val)
{
struct vmcb *vmcb;
struct vmcb_state *state;
struct vmcb_segment *seg;
int err, dirtyseg;
vmcb = svm_get_vmcb(vcpu);
state = &vmcb->state;
dirtyseg = 0;
err = 0;
if (VMCB_ACCESS_OK(ident))
return (vmcb_access(vcpu, 1, ident, &val));
switch (ident) {
case VM_REG_GUEST_CR0:
state->cr0 = val;
svm_set_dirty(vcpu, VMCB_CACHE_CR);
break;
case VM_REG_GUEST_CR2:
state->cr2 = val;
svm_set_dirty(vcpu, VMCB_CACHE_CR2);
break;
case VM_REG_GUEST_CR3:
state->cr3 = val;
svm_set_dirty(vcpu, VMCB_CACHE_CR);
break;
case VM_REG_GUEST_CR4:
state->cr4 = val;
svm_set_dirty(vcpu, VMCB_CACHE_CR);
break;
case VM_REG_GUEST_DR6:
state->dr6 = val;
svm_set_dirty(vcpu, VMCB_CACHE_DR);
break;
case VM_REG_GUEST_DR7:
state->dr7 = val;
svm_set_dirty(vcpu, VMCB_CACHE_DR);
break;
case VM_REG_GUEST_EFER:
/* EFER_SVM must always be set when the guest is executing */
state->efer = val | EFER_SVM;
svm_set_dirty(vcpu, VMCB_CACHE_CR);
break;
case VM_REG_GUEST_RAX:
state->rax = val;
break;
case VM_REG_GUEST_RFLAGS:
state->rflags = val;
break;
case VM_REG_GUEST_RIP:
state->rip = val;
break;
case VM_REG_GUEST_RSP:
state->rsp = val;
break;
case VM_REG_GUEST_CS:
case VM_REG_GUEST_DS:
case VM_REG_GUEST_ES:
case VM_REG_GUEST_SS:
dirtyseg = 1; /* FALLTHROUGH */
case VM_REG_GUEST_FS:
case VM_REG_GUEST_GS:
case VM_REG_GUEST_LDTR:
case VM_REG_GUEST_TR:
seg = vmcb_segptr(vmcb, ident);
KASSERT(seg != NULL, ("%s: unable to get segment %d from VMCB",
__func__, ident));
seg->selector = val;
if (dirtyseg)
svm_set_dirty(vcpu, VMCB_CACHE_SEG);
break;
case VM_REG_GUEST_GDTR:
case VM_REG_GUEST_IDTR:
/* GDTR and IDTR don't have segment selectors */
err = EINVAL;
break;
default:
err = EINVAL;
break;
}
return (err);
}
int
vmcb_seg(struct vmcb *vmcb, int ident, struct vmcb_segment *seg2)
{
struct vmcb_segment *seg;
seg = vmcb_segptr(vmcb, ident);
if (seg != NULL) {
bcopy(seg, seg2, sizeof(struct vmcb_segment));
return (0);
} else {
return (EINVAL);
}
}
int
vmcb_setdesc(struct svm_vcpu *vcpu, int reg, struct seg_desc *desc)
{
struct vmcb *vmcb;
struct vmcb_segment *seg;
uint16_t attrib;
vmcb = svm_get_vmcb(vcpu);
seg = vmcb_segptr(vmcb, reg);
KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
__func__, reg));
seg->base = desc->base;
seg->limit = desc->limit;
if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
/*
* Map seg_desc access to VMCB attribute format.
*
* SVM uses the 'P' bit in the segment attributes to indicate a
* NULL segment so clear it if the segment is marked unusable.
*/
attrib = ((desc->access & 0xF000) >> 4) | (desc->access & 0xFF);
if (SEG_DESC_UNUSABLE(desc->access)) {
attrib &= ~0x80;
}
seg->attrib = attrib;
}
SVM_CTR4(vcpu, "Setting desc %d: base (%#lx), limit (%#x), "
"attrib (%#x)", reg, seg->base, seg->limit, seg->attrib);
switch (reg) {
case VM_REG_GUEST_CS:
case VM_REG_GUEST_DS:
case VM_REG_GUEST_ES:
case VM_REG_GUEST_SS:
svm_set_dirty(vcpu, VMCB_CACHE_SEG);
break;
case VM_REG_GUEST_GDTR:
case VM_REG_GUEST_IDTR:
svm_set_dirty(vcpu, VMCB_CACHE_DT);
break;
default:
break;
}
return (0);
}
int
vmcb_getdesc(struct svm_vcpu *vcpu, int reg, struct seg_desc *desc)
{
struct vmcb *vmcb;
struct vmcb_segment *seg;
vmcb = svm_get_vmcb(vcpu);
seg = vmcb_segptr(vmcb, reg);
KASSERT(seg != NULL, ("%s: invalid segment descriptor %d",
__func__, reg));
desc->base = seg->base;
desc->limit = seg->limit;
desc->access = 0;
if (reg != VM_REG_GUEST_GDTR && reg != VM_REG_GUEST_IDTR) {
/* Map seg_desc access to VMCB attribute format */
desc->access = ((seg->attrib & 0xF00) << 4) |
(seg->attrib & 0xFF);
/*
* VT-x uses bit 16 to indicate a segment that has been loaded
* with a NULL selector (aka unusable). The 'desc->access'
* field is interpreted in the VT-x format by the
* processor-independent code.
*
* SVM uses the 'P' bit to convey the same information so
* convert it into the VT-x format. For more details refer to
* section "Segment State in the VMCB" in APMv2.
*/
if (reg != VM_REG_GUEST_CS && reg != VM_REG_GUEST_TR) {
if ((desc->access & 0x80) == 0)
desc->access |= 0x10000; /* Unusable segment */
}
}
return (0);
}
#ifdef BHYVE_SNAPSHOT
int
vmcb_getany(struct svm_vcpu *vcpu, int ident, uint64_t *val)
{
int error = 0;
if (ident >= VM_REG_LAST) {
error = EINVAL;
goto err;
}
error = vmcb_read(vcpu, ident, val);
err:
return (error);
}
int
vmcb_setany(struct svm_vcpu *vcpu, int ident, uint64_t val)
{
int error = 0;
if (ident >= VM_REG_LAST) {
error = EINVAL;
goto err;
}
error = vmcb_write(vcpu, ident, val);
err:
return (error);
}
int
vmcb_snapshot_desc(struct svm_vcpu *vcpu, int reg,
struct vm_snapshot_meta *meta)
{
int ret;
struct seg_desc desc;
if (meta->op == VM_SNAPSHOT_SAVE) {
ret = vmcb_getdesc(vcpu, reg, &desc);
if (ret != 0)
goto done;
SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
} else if (meta->op == VM_SNAPSHOT_RESTORE) {
SNAPSHOT_VAR_OR_LEAVE(desc.base, meta, ret, done);
SNAPSHOT_VAR_OR_LEAVE(desc.limit, meta, ret, done);
SNAPSHOT_VAR_OR_LEAVE(desc.access, meta, ret, done);
ret = vmcb_setdesc(vcpu, reg, &desc);
if (ret != 0)
goto done;
} else {
ret = EINVAL;
goto done;
}
done:
return (ret);
}
int
vmcb_snapshot_any(struct svm_vcpu *vcpu, int ident,
struct vm_snapshot_meta *meta)
{
int ret;
uint64_t val;
if (meta->op == VM_SNAPSHOT_SAVE) {
ret = vmcb_getany(vcpu, ident, &val);
if (ret != 0)
goto done;
SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
} else if (meta->op == VM_SNAPSHOT_RESTORE) {
SNAPSHOT_VAR_OR_LEAVE(val, meta, ret, done);
ret = vmcb_setany(vcpu, ident, val);
if (ret != 0)
goto done;
} else {
ret = EINVAL;
goto done;
}
done:
return (ret);
}
#endif
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