On Thu, Jun 20, 2013 at 06:45:22PM +0800, Arthur Chunqi Li wrote:
> Change two functions (test_mmx_movq_mf and test_movabs) using
> unified trap_emulator.
>
> Signed-off-by: Arthur Chunqi Li <[email protected]>
> ---
> x86/emulator.c | 70
> ++++++++++++--------------------------------------------
> 1 file changed, 15 insertions(+), 55 deletions(-)
>
> diff --git a/x86/emulator.c b/x86/emulator.c
> index b3626fa..16d63e0 100644
> --- a/x86/emulator.c
> +++ b/x86/emulator.c
> @@ -772,38 +772,19 @@ static void advance_rip_by_3_and_note_exception(struct
> ex_regs *regs)
> static void test_mmx_movq_mf(uint64_t *mem, uint8_t *insn_page,
> uint8_t *alt_insn_page, void *insn_ram)
> {
> - uint16_t fcw = 0; // all exceptions unmasked
> - ulong *cr3 = (ulong *)read_cr3();
> -
> - write_cr0(read_cr0() & ~6); // TS, EM
> - // Place a trapping instruction in the page to trigger a VMEXIT
> - insn_page[0] = 0x89; // mov %eax, (%rax)
> - insn_page[1] = 0x00;
> - insn_page[2] = 0x90; // nop
> - insn_page[3] = 0xc3; // ret
> - // Place the instruction we want the hypervisor to see in the alternate
> page
> - alt_insn_page[0] = 0x0f; // movq %mm0, (%rax)
> - alt_insn_page[1] = 0x7f;
> - alt_insn_page[2] = 0x00;
> - alt_insn_page[3] = 0xc3; // ret
> + uint16_t fcw = 0; /* all exceptions unmasked */
> + u8 alt_insn[] = {0x0f, 0x7f, 0x00}; /* movq %mm0, (%rax) */
Lets introduce something akin to MK_INSN in x86/realmode.c.
> + void *stack = alloc_page();
>
> + write_cr0(read_cr0() & ~6); /* TS, EM */
> exceptions = 0;
> handle_exception(MF_VECTOR, advance_rip_by_3_and_note_exception);
> -
> - // 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);
> asm volatile("fninit; fldcw %0" : : "m"(fcw));
> - asm volatile("fldz; fldz; fdivp"); // generate exception
> - invlpg(insn_ram);
> - // Load code TLB
> - asm volatile("call *%0" : : "r"(insn_ram + 3));
> - 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), "a"(mem));
> - // exit MMX mode
> + asm volatile("fldz; fldz; fdivp"); /* generate exception */
> +
> + inregs = (struct regs){ .rsp=(u64)stack+1024 };
> + trap_emulator(mem, alt_insn, 3);
> + /* exit MMX mode */
> asm volatile("fnclex; emms");
> report("movq mmx generates #MF", exceptions == 1);
> handle_exception(MF_VECTOR, 0);
> @@ -812,33 +793,12 @@ static void test_mmx_movq_mf(uint64_t *mem, uint8_t
> *insn_page,
> static void test_movabs(uint64_t *mem, uint8_t *insn_page,
> uint8_t *alt_insn_page, void *insn_ram)
> {
> - uint64_t val = 0;
> - ulong *cr3 = (ulong *)read_cr3();
> -
> - // Pad with RET instructions
> - memset(insn_page, 0xc3, 4096);
> - memset(alt_insn_page, 0xc3, 4096);
> - // Place a trapping instruction in the page to trigger a VMEXIT
> - insn_page[0] = 0x89; // mov %eax, (%rax)
> - insn_page[1] = 0x00;
> - // Place the instruction we want the hypervisor to see in the alternate
> - // page. A buggy hypervisor will fetch a 32-bit immediate and return
> - // 0xffffffffc3c3c3c3.
> - alt_insn_page[0] = 0x48; // mov $0xc3c3c3c3c3c3c3c3, %rcx
> - alt_insn_page[1] = 0xb9;
> -
> - // 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);
> - // Load code TLB
> - invlpg(insn_ram);
> - asm volatile("call *%0" : : "r"(insn_ram + 3));
> - // Trap, let hypervisor emulate at alt_insn_page
> - install_page(cr3, virt_to_phys(alt_insn_page), insn_ram);
> - asm volatile("call *%1" : "=c"(val) : "r"(insn_ram), "a"(mem), "c"(0));
> - report("64-bit mov imm", val == 0xc3c3c3c3c3c3c3c3);
> + /* mov $0x9090909090909090, %rcx */
> + uint8_t alt_insn[] = {0x48, 0xb9, 0x90, 0x90, 0x90,
> + 0x90, 0x90, 0x90, 0x90, 0x90};
> + inregs = (struct regs){ 0 };
> + trap_emulator(mem, alt_insn, 10);
> + report("64-bit mov imm2", outregs.rcx == 0x9090909090909090);
> }
>
> static void test_crosspage_mmio(volatile uint8_t *mem)
> --
> 1.7.9.5
--
Gleb.
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