linux-kernel - Re: [bug report] GICv4.1: vSGI remains pending across the guest reset

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZX8xLhFFqTXRFQtd@linux.dev>
Date: Sun, 17 Dec 2023 17:34:38 +0000
From: Oliver Upton <oliver.upton@...ux.dev>
To: Marc Zyngier <maz@...nel.org>
Cc: Kunkun Jiang <jiangkunkun@...wei.com>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Jean-Philippe Brucker <jean-philippe@...aro.org>,
	"moderated list:ARM SMMU DRIVERS" <linux-arm-kernel@...ts.infradead.org>,
	kvmarm@...ts.linux.dev, open list <linux-kernel@...r.kernel.org>,
	"wanghaibin.wang@...wei.com" <wanghaibin.wang@...wei.com>
Subject: Re: [bug report] GICv4.1: vSGI remains pending across the guest reset

On Sun, Dec 17, 2023 at 05:33:16PM +0000, Oliver Upton wrote:
> On Sun, Dec 17, 2023 at 11:26:15AM +0000, Marc Zyngier wrote:
> 
> [...]
> 
> > But this has *nothing* to do with the guest. This is the *host*
> > userspace performing a write to the redistributor view, which has
> > different semantics. Which is why your earlier description made no
> > sense to me.
> > 
> > I think the problem is slightly larger than what you describe. A write
> > to ISPENDR0 should be propagated to the ITS for any values of the
> > latch, just like this happens on enabling HW-backed SGIs.
> > 
> > Can you please give this a go?
> 
> What do you think about using this as an opportunity for a bit of
> cleanup? It'd be nice unify the various MMIO and uaccess handlers for
> SPENDING + CPENDING while being careful about the arch_timer interrupt.

Cut myself off... Meant to say that user writes to SPENDING for GICv3
can then be treated as:

> 	clear = ~val;
> 	vgic_uaccess_write_spending(val);
> 	vgic_uaccess_write_cpending(clear);

-- 
Thanks,
Oliver