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Diffstat (limited to 'arch/x86/kvm/emulate.c')
-rw-r--r--arch/x86/kvm/emulate.c93
1 files changed, 52 insertions, 41 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 205b17eed93c..e4e833d3d7d7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -161,6 +161,7 @@
#define Fastop ((u64)1 << 44) /* Use opcode::u.fastop */
#define NoWrite ((u64)1 << 45) /* No writeback */
#define SrcWrite ((u64)1 << 46) /* Write back src operand */
+#define NoMod ((u64)1 << 47) /* Mod field is ignored */
#define DstXacc (DstAccLo | SrcAccHi | SrcWrite)
@@ -1077,7 +1078,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
ctxt->modrm_rm |= (ctxt->modrm & 0x07);
ctxt->modrm_seg = VCPU_SREG_DS;
- if (ctxt->modrm_mod == 3) {
+ if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) {
op->type = OP_REG;
op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,
@@ -1324,7 +1325,8 @@ static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
rc->end = n * size;
}
- if (ctxt->rep_prefix && !(ctxt->eflags & EFLG_DF)) {
+ if (ctxt->rep_prefix && (ctxt->d & String) &&
+ !(ctxt->eflags & EFLG_DF)) {
ctxt->dst.data = rc->data + rc->pos;
ctxt->dst.type = OP_MEM_STR;
ctxt->dst.count = (rc->end - rc->pos) / size;
@@ -1409,11 +1411,11 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
}
/* Does not support long mode */
-static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
- u16 selector, int seg)
+static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+ u16 selector, int seg, u8 cpl, bool in_task_switch)
{
struct desc_struct seg_desc, old_desc;
- u8 dpl, rpl, cpl;
+ u8 dpl, rpl;
unsigned err_vec = GP_VECTOR;
u32 err_code = 0;
bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */
@@ -1441,7 +1443,6 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
}
rpl = selector & 3;
- cpl = ctxt->ops->cpl(ctxt);
/* NULL selector is not valid for TR, CS and SS (except for long mode) */
if ((seg == VCPU_SREG_CS
@@ -1486,6 +1487,9 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
goto exception;
break;
case VCPU_SREG_CS:
+ if (in_task_switch && rpl != dpl)
+ goto exception;
+
if (!(seg_desc.type & 8))
goto exception;
@@ -1543,6 +1547,13 @@ exception:
return X86EMUL_PROPAGATE_FAULT;
}
+static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+ u16 selector, int seg)
+{
+ u8 cpl = ctxt->ops->cpl(ctxt);
+ return __load_segment_descriptor(ctxt, selector, seg, cpl, false);
+}
+
static void write_register_operand(struct operand *op)
{
/* The 4-byte case *is* correct: in 64-bit mode we zero-extend. */
@@ -2404,6 +2415,7 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
struct tss_segment_16 *tss)
{
int ret;
+ u8 cpl;
ctxt->_eip = tss->ip;
ctxt->eflags = tss->flag | 2;
@@ -2426,23 +2438,25 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
set_segment_selector(ctxt, tss->ss, VCPU_SREG_SS);
set_segment_selector(ctxt, tss->ds, VCPU_SREG_DS);
+ cpl = tss->cs & 3;
+
/*
* Now load segment descriptors. If fault happens at this stage
* it is handled in a context of new task
*/
- ret = load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR);
+ ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES);
+ ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS);
+ ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS);
+ ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS);
+ ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
@@ -2496,7 +2510,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
struct tss_segment_32 *tss)
{
- tss->cr3 = ctxt->ops->get_cr(ctxt, 3);
+ /* CR3 and ldt selector are not saved intentionally */
tss->eip = ctxt->_eip;
tss->eflags = ctxt->eflags;
tss->eax = reg_read(ctxt, VCPU_REGS_RAX);
@@ -2514,13 +2528,13 @@ static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
tss->ds = get_segment_selector(ctxt, VCPU_SREG_DS);
tss->fs = get_segment_selector(ctxt, VCPU_SREG_FS);
tss->gs = get_segment_selector(ctxt, VCPU_SREG_GS);
- tss->ldt_selector = get_segment_selector(ctxt, VCPU_SREG_LDTR);
}
static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
struct tss_segment_32 *tss)
{
int ret;
+ u8 cpl;
if (ctxt->ops->set_cr(ctxt, 3, tss->cr3))
return emulate_gp(ctxt, 0);
@@ -2539,7 +2553,8 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
/*
* SDM says that segment selectors are loaded before segment
- * descriptors
+ * descriptors. This is important because CPL checks will
+ * use CS.RPL.
*/
set_segment_selector(ctxt, tss->ldt_selector, VCPU_SREG_LDTR);
set_segment_selector(ctxt, tss->es, VCPU_SREG_ES);
@@ -2553,43 +2568,38 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
* If we're switching between Protected Mode and VM86, we need to make
* sure to update the mode before loading the segment descriptors so
* that the selectors are interpreted correctly.
- *
- * Need to get rflags to the vcpu struct immediately because it
- * influences the CPL which is checked at least when loading the segment
- * descriptors and when pushing an error code to the new kernel stack.
- *
- * TODO Introduce a separate ctxt->ops->set_cpl callback
*/
- if (ctxt->eflags & X86_EFLAGS_VM)
+ if (ctxt->eflags & X86_EFLAGS_VM) {
ctxt->mode = X86EMUL_MODE_VM86;
- else
+ cpl = 3;
+ } else {
ctxt->mode = X86EMUL_MODE_PROT32;
-
- ctxt->ops->set_rflags(ctxt, ctxt->eflags);
+ cpl = tss->cs & 3;
+ }
/*
* Now load segment descriptors. If fault happenes at this stage
* it is handled in a context of new task
*/
- ret = load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR);
+ ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES);
+ ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS);
+ ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS);
+ ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS);
+ ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS);
+ ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
- ret = load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS);
+ ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl, true);
if (ret != X86EMUL_CONTINUE)
return ret;
@@ -2604,6 +2614,8 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
struct tss_segment_32 tss_seg;
int ret;
u32 new_tss_base = get_desc_base(new_desc);
+ u32 eip_offset = offsetof(struct tss_segment_32, eip);
+ u32 ldt_sel_offset = offsetof(struct tss_segment_32, ldt_selector);
ret = ops->read_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
&ctxt->exception);
@@ -2613,8 +2625,9 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
save_state_to_tss32(ctxt, &tss_seg);
- ret = ops->write_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
- &ctxt->exception);
+ /* Only GP registers and segment selectors are saved */
+ ret = ops->write_std(ctxt, old_tss_base + eip_offset, &tss_seg.eip,
+ ldt_sel_offset - eip_offset, &ctxt->exception);
if (ret != X86EMUL_CONTINUE)
/* FIXME: need to provide precise fault address */
return ret;
@@ -3386,10 +3399,6 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
if (efer & EFER_LMA)
rsvd = CR3_L_MODE_RESERVED_BITS;
- else if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PAE)
- rsvd = CR3_PAE_RESERVED_BITS;
- else if (ctxt->ops->get_cr(ctxt, 0) & X86_CR0_PG)
- rsvd = CR3_NONPAE_RESERVED_BITS;
if (new_val & rsvd)
return emulate_gp(ctxt, 0);
@@ -3869,10 +3878,12 @@ static const struct opcode twobyte_table[256] = {
N, N, N, N, N, N, N, N,
D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
/* 0x20 - 0x2F */
- DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
- DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
- IIP(ModRM | SrcMem | Priv | Op3264, em_cr_write, cr_write, check_cr_write),
- IIP(ModRM | SrcMem | Priv | Op3264, em_dr_write, dr_write, check_dr_write),
+ DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read),
+ DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),
+ IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_cr_write, cr_write,
+ check_cr_write),
+ IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_dr_write, dr_write,
+ check_dr_write),
N, N, N, N,
GP(ModRM | DstReg | SrcMem | Mov | Sse, &pfx_0f_28_0f_29),
GP(ModRM | DstMem | SrcReg | Mov | Sse, &pfx_0f_28_0f_29),
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-21 08:36:47 +0200