kvm/emulate: fix a -Werror=cast-function-type

arch/x86/kvm/emulate.c: In function 'x86_emulate_insn':
arch/x86/kvm/emulate.c:5686:22: error: cast between incompatible
function types from 'int (*)(struct x86_emulate_ctxt *)' to 'void
(*)(struct fastop *)' [-Werror=cast-function-type]
    rc = fastop(ctxt, (fastop_t)ctxt->execute);

Fix it by using an unnamed union of a (*execute) function pointer and a
(*fastop) function pointer.

Fixes: 3009afc6e3 ("KVM: x86: Use a typedef for fastop functions")
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Qian Cai 2020-02-17 11:48:26 -05:00 committed by Paolo Bonzini
parent 147f1a1fe5
commit b78a8552d7
2 changed files with 26 additions and 23 deletions

View File

@ -292,6 +292,14 @@ enum x86emul_mode {
#define X86EMUL_SMM_MASK (1 << 6)
#define X86EMUL_SMM_INSIDE_NMI_MASK (1 << 7)
/*
* fastop functions are declared as taking a never-defined fastop parameter,
* so they can't be called from C directly.
*/
struct fastop;
typedef void (*fastop_t)(struct fastop *);
struct x86_emulate_ctxt {
const struct x86_emulate_ops *ops;
@ -324,7 +332,10 @@ struct x86_emulate_ctxt {
struct operand src;
struct operand src2;
struct operand dst;
int (*execute)(struct x86_emulate_ctxt *ctxt);
union {
int (*execute)(struct x86_emulate_ctxt *ctxt);
fastop_t fop;
};
int (*check_perm)(struct x86_emulate_ctxt *ctxt);
/*
* The following six fields are cleared together,

View File

@ -191,25 +191,6 @@
#define NR_FASTOP (ilog2(sizeof(ulong)) + 1)
#define FASTOP_SIZE 8
/*
* fastop functions have a special calling convention:
*
* dst: rax (in/out)
* src: rdx (in/out)
* src2: rcx (in)
* flags: rflags (in/out)
* ex: rsi (in:fastop pointer, out:zero if exception)
*
* Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for
* different operand sizes can be reached by calculation, rather than a jump
* table (which would be bigger than the code).
*
* fastop functions are declared as taking a never-defined fastop parameter,
* so they can't be called from C directly.
*/
struct fastop;
struct opcode {
u64 flags : 56;
u64 intercept : 8;
@ -311,8 +292,19 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt)
#define ON64(x)
#endif
typedef void (*fastop_t)(struct fastop *);
/*
* fastop functions have a special calling convention:
*
* dst: rax (in/out)
* src: rdx (in/out)
* src2: rcx (in)
* flags: rflags (in/out)
* ex: rsi (in:fastop pointer, out:zero if exception)
*
* Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for
* different operand sizes can be reached by calculation, rather than a jump
* table (which would be bigger than the code).
*/
static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
#define __FOP_FUNC(name) \
@ -5683,7 +5675,7 @@ special_insn:
if (ctxt->execute) {
if (ctxt->d & Fastop)
rc = fastop(ctxt, (fastop_t)ctxt->execute);
rc = fastop(ctxt, ctxt->fop);
else
rc = ctxt->execute(ctxt);
if (rc != X86EMUL_CONTINUE)