On Wed, Sep 10, 2025, Hou Wenlong wrote:
> Similar to the global disable test case in x86's debug_regs test, use
> 'KVM_FEP' to trigger instruction emulation in order to verify the guest
> debug DR7.GD checking during instruction emulation.
>
> Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
> ---
> tools/testing/selftests/kvm/x86/debug_regs.c | 25 +++++++++++++++++++-
> 1 file changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/kvm/x86/debug_regs.c b/tools/testing/selftests/kvm/x86/debug_regs.c
> index 2d814c1d1dc4..ba80b77c2869 100644
> --- a/tools/testing/selftests/kvm/x86/debug_regs.c
> +++ b/tools/testing/selftests/kvm/x86/debug_regs.c
> @@ -19,6 +19,7 @@
> uint32_t guest_value;
>
> extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
> +extern unsigned char fep_bd_start;
>
> static void guest_code(void)
> {
> @@ -64,6 +65,12 @@ static void guest_code(void)
>
> /* DR6.BD test */
> asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
> +
> + if (is_forced_emulation_enabled) {
> + /* DR6.BD test for emulation */
Put the comment above the if-statement, that way there's no need for curly braces.
Or just drop it entirely; unless the comments more verbose, I don't think it adds
much value.
> + asm volatile(KVM_FEP "fep_bd_start: mov %%dr0, %%rax" : : : "rax");
> + }
> +
> GUEST_DONE();
> }
>
> @@ -185,7 +192,7 @@ int main(void)
> target_dr6);
> }
>
> - /* Finally test global disable */
> + /* test global disable */
> memset(&debug, 0, sizeof(debug));
> debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
> debug.arch.debugreg[7] = 0x400 | DR7_GD;
> @@ -202,6 +209,22 @@ int main(void)
> run->debug.arch.pc, target_rip, run->debug.arch.dr6,
> target_dr6);
>
> + /* test global disable in emulation */
> + if (is_forced_emulation_enabled) {
> + /* Skip the 3-bytes "mov dr0" */
> + vcpu_skip_insn(vcpu, 3);
> + vcpu_run(vcpu);
> + TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
> + run->debug.arch.exception == DB_VECTOR &&
> + run->debug.arch.pc == CAST_TO_RIP(fep_bd_start) &&
> + run->debug.arch.dr6 == target_dr6,
> + "DR7.GD: exit %d exception %d rip 0x%llx "
> + "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
> + run->exit_reason, run->debug.arch.exception,
> + run->debug.arch.pc, target_rip, run->debug.arch.dr6,
> + target_dr6);
> + }
> +
> /* Disable all debug controls, run to the end */
> memset(&debug, 0, sizeof(debug));
> vcpu_guest_debug_set(vcpu, &debug);
> --
> 2.31.1
>