[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] x86/HVM: don't mark evtchn upcall vector as pending when vLAPIC is disabled
- To: Roger Pau Monné <roger.pau@xxxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Thu, 24 Nov 2022 10:06:48 +0100
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=TlgS9y3dPfl/htubr3kT3GwI+dfAQ+fglh8R0sG3A+M=; b=dZiYU1wctHEuHZPuY5AebrPXrDpdRFGTnAHjlXLf5/SYwtdg4hpnevT4nI3gNXyIZCvu7ngkgU1fvnerdgSatLGaa0UWeoNeWoTscPTJ9bXteQOzQA3YoCoRIfXKON/6cc6VqTAu77gqOtzuLInfVg2BxwOXzGf+OCd/AByMSetdyX/Ev+iODA0oGbEoy3mgYp/lxrRYD07+wsZQ/31TYXy7roqpS9X03iNbhoCCNPEBfumAec6WtKhT4LSYxrR9xxWogS75ZW/uRoOQE4FpJ7tWflaqIbKlEiL5X5i/Z/gHPXvi5HU2/G5quEQQxWdxzGwGYKthwxmyEVQh9lsMuQ==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=aF5jYbU7BD4Um5SCzIevs3VWhHp3a0LxvWuEOUbv0OlgDipSp2ltT0u+CtJxsgV0+pEdEoSXdQl1drS/xJdcPpGK7P3hzlMbGdywM5NZGQmlruKr7HFNqstmmDRtPczleTg9hFC5zhOi5zWsDfOlRLXzWahAbIDFPOBUVSdmAUN+XW9bhNThmMMVl97c8+y/ORdqT6TYXxvljdBdnsmfocrcXlJDvMogg7NrhKch7c1NM2H12sC1BmE0Nuo8YiWCkvwAxHRH8Eh9mlmYR1TjWenDxEnxQNm1fM7hp+r89RypmSFjpDku4HwWT2qvTmJIei8EnTq2vJys+RK8ebmssA==
- Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com;
- Cc: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Paul Durrant <paul@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- Delivery-date: Thu, 24 Nov 2022 09:06:54 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 24.11.2022 09:42, Roger Pau Monné wrote:
> On Thu, Nov 24, 2022 at 08:59:00AM +0100, Jan Beulich wrote:
>> One related question here is whether vlapic_do_init() shouldn't have
>> the non-architectural side effect of clearing evtchn_upcall_pending.
>> While this again violates the principle of the hypervisor only ever
>> setting that bit, it would deal with the risk of no further event
>> injection once the flag is set, considering that vlapic_do_init()
>> clears IRR (and ISR).
>
> That would seem sensible to me, and was kind of what I was suggesting
> in:
>
> https://lore.kernel.org/xen-devel/Y3eO0bMKRPYJc2yQ@Air-de-Roger/
Oh, I didn't read it that way, as there you said "when it is enabled",
whereas here I'm suggesting to do so when it is being (re)initialized.
But, as said both above and in the reply, we'd need to be sure of the
resulting behavioral change (kind of an ABI one) being acceptable.
Jan
|
