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KVM: x86 emulator: Add check_perm callback

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This patch adds a check_perm callback for each opcode into
the instruction emulator. This will be used to do all
necessary permission checks on instructions before checking
whether they are intercepted or not.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Joerg Roedel
2011-04-04 12:39:25 +02:00
committed by Avi Kivity
parent 775fde8648
commit d09beabd7c
2 changed files with 15 additions and 0 deletions
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1
arch/x86/include/asm/kvm_emulate.h
View File

@@ -222,6 +222,7 @@ struct decode_cache {
u8 seg_override; u8 seg_override;
unsigned int d; unsigned int d;
int (*execute)(struct x86_emulate_ctxt *ctxt); int (*execute)(struct x86_emulate_ctxt *ctxt);
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
unsigned long regs[NR_VCPU_REGS]; unsigned long regs[NR_VCPU_REGS];
unsigned long eip; unsigned long eip;
/* modrm */ /* modrm */

14
arch/x86/kvm/emulate.c
View File

@@ -111,6 +111,7 @@ struct opcode {
struct group_dual *gdual; struct group_dual *gdual;
struct gprefix *gprefix; struct gprefix *gprefix;
} u; } u;
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
}; };
struct group_dual { struct group_dual {
@@ -2425,12 +2426,17 @@ static int em_movdqu(struct x86_emulate_ctxt *ctxt)
#define D(_y) { .flags = (_y) } #define D(_y) { .flags = (_y) }
#define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i } #define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
#define DIP(_y, _i, _p) { .flags = (_y), .intercept = x86_intercept_##_i, \
.check_perm = (_p) }
#define N D(0) #define N D(0)
#define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) } #define G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }
#define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) } #define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }
#define I(_f, _e) { .flags = (_f), .u.execute = (_e) } #define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
#define II(_f, _e, _i) \ #define II(_f, _e, _i) \
{ .flags = (_f), .u.execute = (_e), .intercept = x86_intercept_##_i } { .flags = (_f), .u.execute = (_e), .intercept = x86_intercept_##_i }
#define IIP(_f, _e, _i, _p) \
{ .flags = (_f), .u.execute = (_e), .intercept = x86_intercept_##_i, \
.check_perm = (_p) }
#define GP(_f, _g) { .flags = ((_f) | Prefix), .u.gprefix = (_g) } #define GP(_f, _g) { .flags = ((_f) | Prefix), .u.gprefix = (_g) }
#define D2bv(_f) D((_f) | ByteOp), D(_f) #define D2bv(_f) D((_f) | ByteOp), D(_f)
@@ -2873,6 +2879,7 @@ done_prefixes:
} }
c->execute = opcode.u.execute; c->execute = opcode.u.execute;
c->check_perm = opcode.check_perm;
c->intercept = opcode.intercept; c->intercept = opcode.intercept;
/* Unrecognised? */ /* Unrecognised? */
@@ -3136,6 +3143,13 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
goto done; goto done;
} }
/* Do instruction specific permission checks */
if (c->check_perm) {
rc = c->check_perm(ctxt);
if (rc != X86EMUL_CONTINUE)
goto done;
}
if (unlikely(ctxt->guest_mode) && c->intercept) { if (unlikely(ctxt->guest_mode) && c->intercept) {
rc = ops->intercept(ctxt, c->intercept, rc = ops->intercept(ctxt, c->intercept,
X86_ICPT_POST_EXCEPT); X86_ICPT_POST_EXCEPT);