Thanks, it's very clear. I'll try to fix it.
Best regards,
Lv, Hui
-----Original Message-----
From: Keir Fraser [mailto:keir.xen@xxxxxxxxx] On Behalf Of Keir Fraser
Sent: Friday, December 31, 2010 5:01 PM
To: Lv, Hui; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] NMI handling in HVM
Change needed to avoid getting a real NMI while handling the fake NMI
created by calling do_nmi() directly. It's a very valid fix.
You'll have to fix this subsequent issue by having a per-cpu bool_t exposed
from self_nmi():
...
this_cpu(is_self_nmi) = 1;
apic_icr_write(APIC_DM_NMI...);
this_cpu(is_self_nmi) = 0;
...
You can check that flag from your NMI handler and if set, and current vcpu
is non-idle, you can go at guest_cpu_user_regs() to get the appropriate cpu
context for profiling. You could even do that check in the generic NMI
handler/dispatcher, and change the regs pointer you pass to the currently
registered specific NMI handler.
-- Keir
On 31/12/2010 01:37, "Lv, Hui" <hui.lv@xxxxxxxxx> wrote:
> Dear all
> I saw a change about NMI handling in C/S 20059. So could
> anyone tell me what¹s the difference of these two ways? We found that after
> changing to Œself_nmi()¹, xenoprofile cannot work correctly. Since
> Œself_nmi()¹ issue a hypervisor nmi and there is no change for xenoprofile to
> record HVM guest regs information.
> --- a/xen/arch/x86/hvm/vmx/vmx.c Fri Aug 14 10:57:24 2009 +0100
> +++ b/xen/arch/x86/hvm/vmx/vmx.c Fri Aug 14 10:58:32 2009 +0100
> @@ -945,8 +945,6 @@ static void vmx_enable_rdtsc_exiting(str
> vmx_vmcs_exit(v);
> }
>
> -void do_nmi(struct cpu_user_regs *);
> -
> static void vmx_init_hypercall_page(struct domain *d, void *hypercall_page)
> {
> char *p;
> @@ -2470,7 +2468,7 @@ asmlinkage void vmx_vmexit_handler(struc
> (X86_EVENTTYPE_NMI << 8) )
> goto exit_and_crash;
> HVMTRACE_0D(NMI);
> - do_nmi(regs); /* Real NMI, vector 2: normal processing. */
> + self_nmi(); /* Real NMI, vector 2: normal processing. */
> break;
> case TRAP_machine_check:
> HVMTRACE_0D(MCE);
>
>
> Best regards!
> Lv,hui
>
>
>
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