Add multibyte NOP test case to kvm-unit-tests. This case can test one
of bugs when booting RHEL5.9 64-bit.
Signed-off-by: Arthur Chunqi Li <yzt...@gmail.com>
---
x86/emulator.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/x86/emulator.c b/x86/emulator.c
index 96576e5..f26c70f 100644
--- a/x86/emulator.c
+++ b/x86/emulator.c
@@ -901,6 +901,37 @@ static void test_simplealu(u32 *mem)
report("test", *mem == 0x8400);
}
+static void test_nopl(uint64_t *mem, uint8_t *insn_page,
+ uint8_t *alt_insn_page, void *insn_ram)
+{
+ 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;
+ insn_page[2] = 0x90; // nop
+ // Place nopl 0x0(%eax) in alt_insn_page for emulator to execuate
+ alt_insn_page[0] = 0x0f; // nop DWORD ptr[EAX]
+ alt_insn_page[1] = 0x1f;
+ alt_insn_page[2] = 0x00;
+
+ // 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 *%0" : : "r"(insn_ram), "a"(mem));
+ report("nopl", 1);
+}
+
int main()
{
void *mem;
@@ -964,6 +995,8 @@ int main()
test_string_io_mmio(mem);
+ test_nopl(mem, insn_page, alt_insn_page, insn_ram);
+
printf("\nSUMMARY: %d tests, %d failures\n", tests, fails);
return fails ? 1 : 0;
}
--
1.7.9.5
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