On Mon, 2021-11-01 at 16:43 +0100, Vitaly Kuznetsov wrote: > Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > > > On 11/08/21 14:29, Maxim Levitsky wrote: > > > Modify debug_regs test to create a pending interrupt > > > and see that it is blocked when single stepping is done > > > with KVM_GUESTDBG_BLOCKIRQ > > > > > > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> > > > --- > > > .../testing/selftests/kvm/x86_64/debug_regs.c | 24 ++++++++++++++++--- > > > 1 file changed, 21 insertions(+), 3 deletions(-) > > > > I haven't looked very much at this, but the test fails. > > > > Same here, > > the test passes on AMD but fails consistently on Intel: > > # ./x86_64/debug_regs > ==== Test Assertion Failure ==== > x86_64/debug_regs.c:179: run->exit_reason == KVM_EXIT_DEBUG && run->debug.arch.exception == DB_VECTOR && run->debug.arch.pc == target_rip && run->debug.arch.dr6 == target_dr6 > pid=13434 tid=13434 errno=0 - Success > 1 0x00000000004027c6: main at debug_regs.c:179 > 2 0x00007f65344cf554: ?? ??:0 > 3 0x000000000040294a: _start at ??:? > SINGLE_STEP[1]: exit 8 exception 1 rip 0x402a25 (should be 0x402a27) dr6 0xffff4ff0 (should be 0xffff4ff0) > > (I know I'm late to the party). Well that is strange. It passes on my intel laptop. Just tested (kvm/queue + qemu master, compiled today) :-( It fails on iteration 1 (and there is iteration 0) which I think means that we start with RIP on sti, and get #DB on start of xor instruction first (correctly), and then we get #DB again on start of xor instruction again? Something very strange. My laptop has i7-7600U. Best regards, Maxim Levitsky > > > Paolo > > > > > diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c > > > index 6097a8283377..5f078db1bcba 100644 > > > --- a/tools/testing/selftests/kvm/x86_64/debug_regs.c > > > +++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c > > > @@ -8,12 +8,15 @@ > > > #include <string.h> > > > #include "kvm_util.h" > > > #include "processor.h" > > > +#include "apic.h" > > > > > > #define VCPU_ID 0 > > > > > > #define DR6_BD (1 << 13) > > > #define DR7_GD (1 << 13) > > > > > > +#define IRQ_VECTOR 0xAA > > > + > > > /* For testing data access debug BP */ > > > uint32_t guest_value; > > > > > > @@ -21,6 +24,11 @@ extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start; > > > > > > static void guest_code(void) > > > { > > > + /* Create a pending interrupt on current vCPU */ > > > + x2apic_enable(); > > > + x2apic_write_reg(APIC_ICR, APIC_DEST_SELF | APIC_INT_ASSERT | > > > + APIC_DM_FIXED | IRQ_VECTOR); > > > + > > > /* > > > * Software BP tests. > > > * > > > @@ -38,12 +46,19 @@ static void guest_code(void) > > > "mov %%rax,%0;\n\t write_data:" > > > : "=m" (guest_value) : : "rax"); > > > > > > - /* Single step test, covers 2 basic instructions and 2 emulated */ > > > + /* > > > + * Single step test, covers 2 basic instructions and 2 emulated > > > + * > > > + * Enable interrupts during the single stepping to see that > > > + * pending interrupt we raised is not handled due to KVM_GUESTDBG_BLOCKIRQ > > > + */ > > > asm volatile("ss_start: " > > > + "sti\n\t" > > > "xor %%eax,%%eax\n\t" > > > "cpuid\n\t" > > > "movl $0x1a0,%%ecx\n\t" > > > "rdmsr\n\t" > > > + "cli\n\t" > > > : : : "eax", "ebx", "ecx", "edx"); > > > > > > /* DR6.BD test */ > > > @@ -72,11 +87,13 @@ int main(void) > > > uint64_t cmd; > > > int i; > > > /* Instruction lengths starting at ss_start */ > > > - int ss_size[4] = { > > > + int ss_size[6] = { > > > + 1, /* sti*/ > > > 2, /* xor */ > > > 2, /* cpuid */ > > > 5, /* mov */ > > > 2, /* rdmsr */ > > > + 1, /* cli */ > > > }; > > > > > > if (!kvm_check_cap(KVM_CAP_SET_GUEST_DEBUG)) { > > > @@ -154,7 +171,8 @@ int main(void) > > > for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) { > > > target_rip += ss_size[i]; > > > CLEAR_DEBUG(); > > > - debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP; > > > + debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP | > > > + KVM_GUESTDBG_BLOCKIRQ; > > > debug.arch.debugreg[7] = 0x00000400; > > > APPLY_DEBUG(); > > > vcpu_run(vm, VCPU_ID); > > >