On 25/02/20 01:09, Oliver Upton wrote:
> On Fri, Feb 7, 2020 at 2:36 AM Oliver Upton <oupton@xxxxxxxxxx> wrote:
>>
>> Test to verify that MTF VM-exits into host are synthesized when the
>> 'monitor trap flag' processor-based VM-execution control is set under
>> various conditions.
>>
>> Expect an MTF VM-exit if instruction execution produces no events other
>> than MTF. Should instruction execution produce a concurrent debug-trap
>> and MTF event, expect an MTF VM-exit with the 'pending debug exceptions'
>> VMCS field set. Expect an MTF VM-exit to follow event delivery should
>> instruction execution generate a higher-priority event, such as a
>> general-protection fault. Lastly, expect an MTF VM-exit to follow
>> delivery of a debug-trap software exception (INT1/INT3/INTO/INT n).
>>
>> Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
>> Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
>> ---
>> x86/vmx.h | 1 +
>> x86/vmx_tests.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 158 insertions(+)
>>
>> diff --git a/x86/vmx.h b/x86/vmx.h
>> index 6214400f2b53..6adf0916564b 100644
>> --- a/x86/vmx.h
>> +++ b/x86/vmx.h
>> @@ -399,6 +399,7 @@ enum Ctrl0 {
>> CPU_NMI_WINDOW = 1ul << 22,
>> CPU_IO = 1ul << 24,
>> CPU_IO_BITMAP = 1ul << 25,
>> + CPU_MTF = 1ul << 27,
>> CPU_MSR_BITMAP = 1ul << 28,
>> CPU_MONITOR = 1ul << 29,
>> CPU_PAUSE = 1ul << 30,
>> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
>> index b31c360c5f3c..0e2c2f8a7d34 100644
>> --- a/x86/vmx_tests.c
>> +++ b/x86/vmx_tests.c
>> @@ -4970,6 +4970,162 @@ static void test_vmx_preemption_timer(void)
>> vmcs_write(EXI_CONTROLS, saved_exit);
>> }
>>
>> +extern unsigned char test_mtf1;
>> +extern unsigned char test_mtf2;
>> +extern unsigned char test_mtf3;
>> +
>> +__attribute__((noclone)) static void test_mtf_guest(void)
>> +{
>> + asm ("vmcall;\n\t"
>> + "out %al, $0x80;\n\t"
>> + "test_mtf1:\n\t"
>> + "vmcall;\n\t"
>> + "out %al, $0x80;\n\t"
>> + "test_mtf2:\n\t"
>> + /*
>> + * Prepare for the 'MOV CR3' test. Attempt to induce a
>> + * general-protection fault by moving a non-canonical address into
>> + * CR3. The 'MOV CR3' instruction does not take an imm64 operand,
>> + * so we must MOV the desired value into a register first.
>> + *
>> + * MOV RAX is done before the VMCALL such that MTF is only enabled
>> + * for the instruction under test.
>> + */
>> + "mov $0x8000000000000000, %rax;\n\t"
>> + "vmcall;\n\t"
>> + "mov %rax, %cr3;\n\t"
>> + "test_mtf3:\n\t"
>> + "vmcall;\n\t"
>> + /*
>> + * ICEBP/INT1 instruction. Though the instruction is now
>> + * documented, don't rely on assemblers enumerating the
>> + * instruction. Resort to hand assembly.
>> + */
>> + ".byte 0xf1;\n\t");
>> +}
>> +
>> +static void test_mtf_gp_handler(struct ex_regs *regs)
>> +{
>> + regs->rip = (unsigned long) &test_mtf3;
>> +}
>> +
>> +static void test_mtf_db_handler(struct ex_regs *regs)
>> +{
>> +}
>> +
>> +static void enable_mtf(void)
>> +{
>> + u32 ctrl0 = vmcs_read(CPU_EXEC_CTRL0);
>> +
>> + vmcs_write(CPU_EXEC_CTRL0, ctrl0 | CPU_MTF);
>> +}
>> +
>> +static void disable_mtf(void)
>> +{
>> + u32 ctrl0 = vmcs_read(CPU_EXEC_CTRL0);
>> +
>> + vmcs_write(CPU_EXEC_CTRL0, ctrl0 & ~CPU_MTF);
>> +}
>> +
>> +static void enable_tf(void)
>> +{
>> + unsigned long rflags = vmcs_read(GUEST_RFLAGS);
>> +
>> + vmcs_write(GUEST_RFLAGS, rflags | X86_EFLAGS_TF);
>> +}
>> +
>> +static void disable_tf(void)
>> +{
>> + unsigned long rflags = vmcs_read(GUEST_RFLAGS);
>> +
>> + vmcs_write(GUEST_RFLAGS, rflags & ~X86_EFLAGS_TF);
>> +}
>> +
>> +static void report_mtf(const char *insn_name, unsigned long exp_rip)
>> +{
>> + unsigned long rip = vmcs_read(GUEST_RIP);
>> +
>> + assert_exit_reason(VMX_MTF);
>> + report(rip == exp_rip, "MTF VM-exit after %s instruction. RIP: 0x%lx (expected 0x%lx)",
>> + insn_name, rip, exp_rip);
>> +}
>> +
>> +static void vmx_mtf_test(void)
>> +{
>> + unsigned long pending_dbg;
>> + handler old_gp, old_db;
>> +
>> + if (!(ctrl_cpu_rev[0].clr & CPU_MTF)) {
>> + printf("CPU does not support the 'monitor trap flag' processor-based VM-execution control.\n");
>> + return;
>> + }
>> +
>> + test_set_guest(test_mtf_guest);
>> +
>> + /* Expect an MTF VM-exit after OUT instruction */
>> + enter_guest();
>> + skip_exit_vmcall();
>> +
>> + enable_mtf();
>> + enter_guest();
>> + report_mtf("OUT", (unsigned long) &test_mtf1);
>> + disable_mtf();
>> +
>> + /*
>> + * Concurrent #DB trap and MTF on instruction boundary. Expect MTF
>> + * VM-exit with populated 'pending debug exceptions' VMCS field.
>> + */
>> + enter_guest();
>> + skip_exit_vmcall();
>> +
>> + enable_mtf();
>> + enable_tf();
>> +
>> + enter_guest();
>> + report_mtf("OUT", (unsigned long) &test_mtf2);
>> + pending_dbg = vmcs_read(GUEST_PENDING_DEBUG);
>> + report(pending_dbg & DR_STEP,
>> + "'pending debug exceptions' field after MTF VM-exit: 0x%lx (expected 0x%lx)",
>> + pending_dbg, (unsigned long) DR_STEP);
>> +
>> + disable_mtf();
>> + disable_tf();
>> + vmcs_write(GUEST_PENDING_DEBUG, 0);
>> +
>> + /*
>> + * #GP exception takes priority over MTF. Expect MTF VM-exit with RIP
>> + * advanced to first instruction of #GP handler.
>> + */
>> + enter_guest();
>> + skip_exit_vmcall();
>> +
>> + old_gp = handle_exception(GP_VECTOR, test_mtf_gp_handler);
>> +
>> + enable_mtf();
>> + enter_guest();
>> + report_mtf("MOV CR3", (unsigned long) get_idt_addr(&boot_idt[GP_VECTOR]));
>> + disable_mtf();
>> +
>> + /*
>> + * Concurrent MTF and privileged software exception (i.e. ICEBP/INT1).
>> + * MTF should follow the delivery of #DB trap, though the SDM doesn't
>> + * provide clear indication of the relative priority.
>> + */
>> + enter_guest();
>> + skip_exit_vmcall();
>> +
>> + handle_exception(GP_VECTOR, old_gp);
>> + old_db = handle_exception(DB_VECTOR, test_mtf_db_handler);
>> +
>> + enable_mtf();
>> + enter_guest();
>> + report_mtf("INT1", (unsigned long) get_idt_addr(&boot_idt[DB_VECTOR]));
>> + disable_mtf();
>> +
>> + enter_guest();
>> + handle_exception(DB_VECTOR, old_db);
>> +}
>> +
>> /*
>> * Tests for VM-execution control fields
>> */
>> @@ -9505,5 +9661,6 @@ struct vmx_test vmx_tests[] = {
>> TEST(atomic_switch_max_msrs_test),
>> TEST(atomic_switch_overflow_msrs_test),
>> TEST(rdtsc_vmexit_diff_test),
>> + TEST(vmx_mtf_test),
>> { NULL, NULL, NULL, NULL, NULL, {0} },
>> };
>> --
>> 2.25.0.341.g760bfbb309-goog
>>
>
> Friendly ping :) (Just on this patch, 1-4 have already been applied)
Done, thanks. I only had to push, since I had applied it already to
test the KVM changes.
Paolo
