Allow some vCPUs to be in SVM nested mode while waiting for an interrupt. Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> --- x86/ipi_stress.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 78 insertions(+), 1 deletion(-) diff --git a/x86/ipi_stress.c b/x86/ipi_stress.c index dea3e605..1a4c5510 100644 --- a/x86/ipi_stress.c +++ b/x86/ipi_stress.c @@ -12,10 +12,12 @@ #include "types.h" #include "alloc_page.h" #include "vmalloc.h" +#include "svm_lib.h" #include "random.h" u64 num_iterations = 100000; float hlt_prob = 0.1; +bool use_svm; volatile bool end_test; #define APIC_TIMER_PERIOD (1000*1000*1000) @@ -25,6 +27,7 @@ struct cpu_test_state { u64 last_isr_count; struct random_state random; int smp_id; + struct svm_vcpu vcpu; } *cpu_states; @@ -71,6 +74,62 @@ static void wait_for_ipi(struct cpu_test_state *state) assert(state->isr_count == old_count + 1); } +#ifdef __x86_64__ +static void l2_guest_wait_for_ipi(struct cpu_test_state *state) +{ + wait_for_ipi(state); + asm volatile("vmmcall"); +} + +static void l2_guest_dummy(void) +{ + while (true) + asm volatile("vmmcall"); +} + +static void wait_for_ipi_in_l2(struct cpu_test_state *state) +{ + u64 old_count = state->isr_count; + struct svm_vcpu *vcpu = &state->vcpu; + bool poll_in_the_guest; + + /* + * if poll_in_the_guest is true, then the guest will run + * with interrupts disabled and it will enable them for one instruction + * (sometimes together with halting) until it receives an interrupts + * + * if poll_in_the_guest is false, the guest will always have + * interrupts enabled and will usually receive the interrupt + * right away, but in case it didn't we will run the guest again + * until it does. + * + */ + poll_in_the_guest = random_decision(&state->random, 50); + + vcpu->regs.rdi = (u64)state; + vcpu->regs.rsp = (ulong)vcpu->stack; + + vcpu->vmcb->save.rip = poll_in_the_guest ? + (ulong)l2_guest_wait_for_ipi : + (ulong)l2_guest_dummy; + + if (!poll_in_the_guest) + vcpu->vmcb->save.rflags |= X86_EFLAGS_IF; + else + vcpu->vmcb->save.rflags &= ~X86_EFLAGS_IF; + + do { + asm volatile("clgi;sti"); + SVM_VMRUN(vcpu); + asm volatile("cli;stgi"); + assert(vcpu->vmcb->control.exit_code == SVM_EXIT_VMMCALL); + + if (poll_in_the_guest) + assert(old_count < state->isr_count); + + } while (old_count == state->isr_count); +} +#endif static void vcpu_init(void *) { @@ -85,6 +144,11 @@ static void vcpu_init(void *) state->random = get_prng(); state->isr_count = 0; state->smp_id = smp_id(); + +#ifdef __x86_64__ + if (use_svm) + svm_vcpu_init(&state->vcpu); +#endif } static void vcpu_code(void *) @@ -111,7 +175,12 @@ static void vcpu_code(void *) break; // wait for the IPI interrupt chain to come back to us - wait_for_ipi(state); +#if __x86_64__ + if (use_svm && random_decision(&state->random, 20)) + wait_for_ipi_in_l2(state); + else +#endif + wait_for_ipi(state); } } @@ -137,6 +206,14 @@ int main(int argc, void **argv) setup_vm(); init_prng(); +#ifdef __x86_64__ + if (this_cpu_has(X86_FEATURE_SVM)) { + use_svm = true; + if (!setup_svm()) + use_svm = false; + } +#endif + cpu_states = calloc(ncpus, sizeof(cpu_states[0])); printf("found %d cpus\n", ncpus); -- 2.34.3