Il 23/10/2013 16:21, Jan Kiszka ha scritto:
> If we both print from L2 and, on timer expiry, from L1, we risk a
> deadlock in L1 on the printf lock that is held by L2 then. Avoid this
> by only printing from L1.
>
> Furthermore, if the timer fails to fire in time, disable it before
> continuing to avoid that it fire later on in different contexts.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> ---
> x86/vmx_tests.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index 8d47bcd..7893a6c 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -128,6 +128,9 @@ void preemption_timer_init()
> preempt_val = 10000000;
> vmcs_write(PREEMPT_TIMER_VALUE, preempt_val);
> preempt_scale = rdmsr(MSR_IA32_VMX_MISC) & 0x1F;
> +
> + if (!(ctrl_exit_rev.clr & EXI_SAVE_PREEMPT))
> + printf("\tSave preemption value is not supported\n");
> }
>
> void preemption_timer_main()
> @@ -137,9 +140,7 @@ void preemption_timer_main()
> printf("\tPreemption timer is not supported\n");
> return;
> }
> - if (!(ctrl_exit_rev.clr & EXI_SAVE_PREEMPT))
> - printf("\tSave preemption value is not supported\n");
> - else {
> + if (ctrl_exit_rev.clr & EXI_SAVE_PREEMPT) {
> set_stage(0);
> vmcall();
> if (get_stage() == 1)
> @@ -148,8 +149,8 @@ void preemption_timer_main()
> while (1) {
> if (((rdtsc() - tsc_val) >> preempt_scale)
> > 10 * preempt_val) {
> - report("Preemption timer", 0);
> - break;
> + set_stage(2);
> + vmcall();
> }
> }
> }
> @@ -170,7 +171,7 @@ int preemption_timer_exit_handler()
> report("Preemption timer", 0);
> else
> report("Preemption timer", 1);
> - return VMX_TEST_VMEXIT;
> + break;
> case VMX_VMCALL:
> switch (get_stage()) {
> case 0:
> @@ -182,24 +183,29 @@ int preemption_timer_exit_handler()
> EXI_SAVE_PREEMPT) & ctrl_exit_rev.clr;
> vmcs_write(EXI_CONTROLS, ctrl_exit);
> }
> - break;
> + vmcs_write(GUEST_RIP, guest_rip + insn_len);
> + return VMX_TEST_RESUME;
> case 1:
> if (vmcs_read(PREEMPT_TIMER_VALUE) >= preempt_val)
> report("Save preemption value", 0);
> else
> report("Save preemption value", 1);
> + vmcs_write(GUEST_RIP, guest_rip + insn_len);
> + return VMX_TEST_RESUME;
> + case 2:
> + report("Preemption timer", 0);
> break;
> default:
> printf("Invalid stage.\n");
> print_vmexit_info();
> - return VMX_TEST_VMEXIT;
> + break;
> }
> - vmcs_write(GUEST_RIP, guest_rip + insn_len);
> - return VMX_TEST_RESUME;
> + break;
> default:
> printf("Unknown exit reason, %d\n", reason);
> print_vmexit_info();
> }
> + vmcs_write(PIN_CONTROLS, vmcs_read(PIN_CONTROLS) & ~PIN_PREEMPT);
> return VMX_TEST_VMEXIT;
> }
>
>
Applied to kvm-unit-tests.git vmx.
Paolo
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