On Thu, Jun 20, 2013 at 06:45:21PM +0800, Arthur Chunqi Li wrote: > Add a function trap_emulator to run an instruction in emulator. > Set inregs first (%rax is invalid because it is used as return > address), put instruction codec in alt_insn and call func with > alt_insn_length. Get results in outregs. > Looks good, some comment bellow.
> Signed-off-by: Arthur Chunqi Li <[email protected]> > --- > lib/libcflat.h | 1 + > lib/string.c | 12 +++++++++ > x86/emulator.c | 78 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 91 insertions(+) > > diff --git a/lib/libcflat.h b/lib/libcflat.h > index 0875bd9..fadc33d 100644 > --- a/lib/libcflat.h > +++ b/lib/libcflat.h > @@ -50,6 +50,7 @@ extern int vsnprintf(char *buf, int size, const char *fmt, > va_list va); > extern void puts(const char *s); > > extern void *memset(void *s, int c, size_t n); > +extern void *memcpy(void *dest, const void *src, size_t n); > > extern long atol(const char *ptr); > #define ARRAY_SIZE(_a) (sizeof(_a)/sizeof((_a)[0])) > diff --git a/lib/string.c b/lib/string.c > index 9dc94a1..e798f86 100644 > --- a/lib/string.c > +++ b/lib/string.c > @@ -42,6 +42,18 @@ void *memset(void *s, int c, size_t n) > return s; > } > > +void *memcpy(void *dest, const void *src, size_t n) > +{ > + size_t i; > + char *a = dest; > + char *b = src; > + > + for (i = 0; i < n; ++i) > + a[i] = b[i]; > + > + return dest; > +} > + memcpy addition should be in separate patch usually, but for unit test it is no a big deal. > long atol(const char *ptr) > { > long acc = 0; > diff --git a/x86/emulator.c b/x86/emulator.c > index 96576e5..b3626fa 100644 > --- a/x86/emulator.c > +++ b/x86/emulator.c > @@ -11,6 +11,15 @@ int fails, tests; > > static int exceptions; > > +struct regs { > + u64 rax, rbx, rcx, rdx; > + u64 rsi, rdi, rsp, rbp; > + u64 r8, r9, r10, r11; > + u64 r12, r13, r14, r15; > + u64 rip, rflags; > +}; > +struct regs inregs, outregs, save; > + > void report(const char *name, int result) > { > ++tests; > @@ -685,6 +694,75 @@ static void test_shld_shrd(u32 *mem) > report("shrd (cl)", *mem == ((0x12345678 >> 3) | (5u << 29))); > } > > +#define INSN_XCHG_ALL \ > + "xchg %rax, 0+save \n\t" \ > + "xchg %rbx, 8+save \n\t" \ > + "xchg %rcx, 16+save \n\t" \ > + "xchg %rdx, 24+save \n\t" \ > + "xchg %rsi, 32+save \n\t" \ > + "xchg %rdi, 40+save \n\t" \ > + "xchg %rsp, 48+save \n\t" \ > + "xchg %rbp, 56+save \n\t" \ > + "xchg %r8, 64+save \n\t" \ > + "xchg %r9, 72+save \n\t" \ > + "xchg %r10, 80+save \n\t" \ > + "xchg %r11, 88+save \n\t" \ > + "xchg %r12, 96+save \n\t" \ > + "xchg %r13, 104+save \n\t" \ > + "xchg %r14, 112+save \n\t" \ > + "xchg %r15, 120+save \n\t" \ > + > +asm( > + ".align 4096\n\t" > + "insn_page:\n\t" > + "ret\n\t" > + "pushf\n\t" > + "push 136+save \n\t" > + "popf \n\t" > + INSN_XCHG_ALL > + "test_insn:\n\t" > + "in (%dx),%al\n\t" > + ".skip 31, 0x90\n\t" > + "test_insn_end:\n\t" > + INSN_XCHG_ALL > + "pushf \n\t" > + "pop 136+save \n\t" > + "popf \n\t" > + "ret \n\t" > + "insn_page_end:\n\t" > + ".align 4096\n\t" > + > + "alt_insn_page:\n\t" > + ". = . + 4096\n\t" > + ".align 4096\n\t" alt_insn_page can be allocated by alloc_page(). > +); > + > +static void trap_emulator(uint64_t *mem, uint8_t* alt_insn, int > alt_insn_length) > +{ > + ulong *cr3 = (ulong *)read_cr3(); > + void *insn_ram; > + extern u8 insn_page[], test_insn[], alt_insn_page[]; > + > + insn_ram = vmap(virt_to_phys(insn_page), 4096); > + memcpy(alt_insn_page, test_insn, 4096); > + memcpy(alt_insn_page + (test_insn - insn_page), alt_insn, > alt_insn_length); > + save = inregs; > + > + /* Load the code TLB with insn_page, but point the page tables at > + alt_insn_page (and keep the data TLB clear, for AMD decode assist). > + This will make the CPU trap on the insn_page instruction but the > + hypervisor will see alt_insn_page. */ > + install_page(cr3, virt_to_phys(insn_page), insn_ram); > + invlpg(insn_ram); > + /* Load code TLB */ > + asm volatile("call *%0" : : "r"(insn_ram)); > + install_page(cr3, virt_to_phys(alt_insn_page), insn_ram); > + /* Trap, let hypervisor emulate at alt_insn_page */ > + asm volatile("call *%0": : "r"(insn_ram+1)); > + > + outregs = save; > +} > + > static void advance_rip_by_3_and_note_exception(struct ex_regs *regs) > { > ++exceptions; > -- > 1.7.9.5 -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
