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Commit d09beabd authored by Joerg Roedel's avatar Joerg Roedel Committed by Avi Kivity
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KVM: x86 emulator: Add check_perm callback 



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: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 775fde86

arch/x86/include/asm/kvm_emulate.h

+1 −0
Original line number Diff line number Diff line
@@ -222,6 +222,7 @@ struct decode_cache { 
	u8 seg_override;

	unsigned int d;

	int (*execute)(struct x86_emulate_ctxt *ctxt);

	int (*check_perm)(struct x86_emulate_ctxt *ctxt);

	unsigned long regs[NR_VCPU_REGS];

	unsigned long eip;

	/* modrm */

arch/x86/kvm/emulate.c

+14 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ struct opcode { 
		struct group_dual *gdual;

		struct gprefix *gprefix;

	} u;

	int (*check_perm)(struct x86_emulate_ctxt *ctxt);

};



struct group_dual {
@@ -2425,12 +2426,17 @@ static int em_movdqu(struct x86_emulate_ctxt *ctxt) 


#define D(_y) { .flags = (_y) }

#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 G(_f, _g) { .flags = ((_f) | Group), .u.group = (_g) }

#define GD(_f, _g) { .flags = ((_f) | Group | GroupDual), .u.gdual = (_g) }

#define I(_f, _e) { .flags = (_f), .u.execute = (_e) }

#define II(_f, _e, _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 D2bv(_f)      D((_f) | ByteOp), D(_f)
@@ -2873,6 +2879,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) 
	}



	c->execute = opcode.u.execute;

	c->check_perm = opcode.check_perm;

	c->intercept = opcode.intercept;



	/* Unrecognised? */
@@ -3136,6 +3143,13 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt) 
		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) {

		rc = ops->intercept(ctxt, c->intercept,

				    X86_ICPT_POST_EXCEPT);