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From: Julien Grall <julien.grall@arm.com>
To: Tamas K Lengyel <tamas@tklengyel.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
	Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [PATCH v4 4/8] monitor: ARM SMC events
Date: Thu, 2 Jun 2016 15:23:52 +0100	[thread overview]
Message-ID: <57504178.40405@arm.com> (raw)
In-Reply-To: <CABfawhmLVQ778o+W3GP=LWkK+u35r3Ek5S1hLUL0gTF98ODouw@mail.gmail.com>


Hello Tamas,

On 01/06/16 16:41, Tamas K Lengyel wrote:
>
> On Jun 1, 2016 05:37, "Julien Grall" <julien.grall@arm.com
> <mailto:julien.grall@arm.com>> wrote:
>  > On 29/05/16 23:37, Tamas K Lengyel wrote:
>  >>
>  >> Add support for monitoring ARM SMC events. This patch only adds the
> required
>  >> bits to enable/disable monitoring and forwarding the event through
> vm_event.
>  >
>  >
>  > Couple of questions:
>  >
>  > - How the vm-event app will differentiate a SMC64 vs a SMC32 call?
>
> Wouldn't cpsr record the guest state when the smc was executed, telling
> us whether it was 32bit or 64bit?

You are right.

>  > - How the vm-event app will know the SMC number (i.e the
>  >
>  > In an AArch64 state, those informations are available from the
> syndrome register (HSR_EL2.ISS).
>
> Good question, it should probably be sent alongside the other registers.
> At the moment my usecase doesn't care about it as I'm just using SMC for
> inducing traps to the vmm but other applications may indeed need this.

In this case, we should either provide HSR_EL2, or decode it provide the 
value.

Note that HSR_EL2.ISS is unknown for ARMv7 (see B3-1431 in ARM DDI 0406C.c).

On ARMv8, ESR_EL2.ISS has a different encoding depending on the state 
(i.e AArch64 or AArch32). See D7-1861 in ARM DDI 0487A.i. Furthermore, 
in AArch32 state, the ARMv8 specs permits to trap conditional SMC 
instructions that fail their condition check (see D7-1897 in ARM DDI 
0406C.c).

So I guess, this need to be abstract in Xen to avoid burden to the 
introspection app.

Regards,

-- 
Julien Grall

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  reply	other threads:[~2016-06-02 14:23 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-29 22:37 [PATCH v4 1/8] monitor: Rename vm_event_monitor_get_capabilities Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 2/8] monitor: Rename vm_event_monitor_guest_request Tamas K Lengyel
2016-05-30  7:05   ` Razvan Cojocaru
2016-05-30 13:51   ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 3/8] monitor: Rename hvm/event to hvm/monitor Tamas K Lengyel
2016-05-30  7:08   ` Razvan Cojocaru
2016-05-30 13:53   ` Jan Beulich
2016-05-29 22:37 ` [PATCH v4 4/8] monitor: ARM SMC events Tamas K Lengyel
2016-06-01 11:37   ` Julien Grall
     [not found]     ` <CABfawhmO9tUG3-OcorfwqdOgZTkjoUk+u=dHySGonBDvobqyKw@mail.gmail.com>
     [not found]       ` <CABfawhmK2GAmQqZMhrgjYzeUZ_XaoyRUPuJxyPK5LJEHwsp5SA@mail.gmail.com>
     [not found]         ` <CABfawh=J1fwinTYKGvJNrFPOsGLSXz6U3GE8fxPz3-KsXSWfbQ@mail.gmail.com>
     [not found]           ` <CABfawhn7zvE=hn0hq1ryH+sW-jdkAXgZM1C2KxwZVUE8pbp8cQ@mail.gmail.com>
2016-06-01 15:41             ` Tamas K Lengyel
2016-06-02 14:23               ` Julien Grall [this message]
2016-06-02 22:31                 ` Tamas K Lengyel
2016-07-04 19:13                 ` Tamas K Lengyel
2016-07-04 20:02                   ` Julien Grall
2016-07-04 21:05                     ` Tamas K Lengyel
2016-07-05  9:58                       ` Julien Grall
2016-05-29 22:37 ` [PATCH v4 5/8] arm/vm_event: get/set registers Tamas K Lengyel
2016-05-30  7:09   ` Razvan Cojocaru
2016-05-30 11:50   ` Jan Beulich
2016-05-30 19:47     ` Tamas K Lengyel
2016-05-30 20:20       ` Julien Grall
2016-05-30 20:37         ` Tamas K Lengyel
2016-05-30 20:46           ` Razvan Cojocaru
2016-05-30 20:53             ` Tamas K Lengyel
2016-05-30 21:35           ` Julien Grall
2016-05-30 21:41             ` Tamas K Lengyel
2016-05-31  7:54           ` Jan Beulich
2016-05-31  8:06             ` Razvan Cojocaru
2016-05-31  8:30               ` Jan Beulich
2016-05-31 16:20             ` Tamas K Lengyel
2016-05-31  7:48       ` Jan Beulich
2016-05-31 16:28         ` Tamas K Lengyel
2016-06-01  8:41           ` Jan Beulich
2016-06-01 11:24             ` Julien Grall
2016-06-01 18:21               ` Tamas K Lengyel
2016-06-01 19:34                 ` Razvan Cojocaru
2016-06-01 19:43                   ` Julien Grall
2016-06-02  7:35                   ` Jan Beulich
2016-06-02  8:26                     ` Razvan Cojocaru
2016-06-02  9:38                       ` Jan Beulich
2016-06-02  9:42                         ` Razvan Cojocaru
2016-06-01 19:38                 ` Julien Grall
2016-06-01 19:49                   ` Julien Grall
2016-06-01 19:50                   ` Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 6/8] tools/libxc: add xc_monitor_privileged_call Tamas K Lengyel
2016-05-29 22:37 ` [PATCH v4 7/8] tools/xen-access: add test-case for ARM SMC Tamas K Lengyel
2016-05-30  9:56   ` Wei Liu
2016-05-29 22:37 ` [PATCH v4 8/8] x86/vm_event: Add HVM debug exception vm_events Tamas K Lengyel
2016-05-30  7:29   ` Razvan Cojocaru
2016-05-30 14:16   ` Jan Beulich
2016-05-30 20:13     ` Tamas K Lengyel
2016-05-30 20:58       ` Andrew Cooper
2016-05-31  7:59       ` Jan Beulich
2016-06-01 21:46         ` Tamas K Lengyel
2016-06-01 22:17           ` Andrew Cooper
2016-06-02  0:01             ` Tamas K Lengyel

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