linux-kernel - Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu

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: <Z6FO04PZtY8fsJhq@linux.dev>
Date: Mon, 3 Feb 2025 15:19:03 -0800
From: Oliver Upton <oliver.upton@...ux.dev>
To: Mark Brown <broonie@...nel.org>, uJap072421@...ux.dev
Cc: Quentin Perret <qperret@...gle.com>, Marc Zyngier <maz@...nel.org>,
	Joey Gouly <joey.gouly@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, Fuad Tabba <tabba@...gle.com>,
	Vincent Donnefort <vdonnefort@...gle.com>,
	Sebastian Ene <sebastianene@...gle.com>,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

On Mon, Feb 03, 2025 at 07:50:44PM +0000, Mark Brown wrote:
> On Wed, Dec 18, 2024 at 07:40:50PM +0000, Quentin Perret wrote:
> > From: Marc Zyngier <maz@...nel.org>
> > 
> > Rather than look-up the hyp vCPU on every run hypercall at EL2,
> > introduce a per-CPU 'loaded_hyp_vcpu' tracking variable which is updated
> > by a pair of load/put hypercalls called directly from
> > kvm_arch_vcpu_{load,put}() when pKVM is enabled.
> 
> Current mainline crashes when running the arch_timer_edge_cases selftest
> in pKVM mode on a LibreTech Le Potato board, with a bisection pointing
> at this change.  The system dies like this:
> 
> # selftests: kvm: arch_timer_edge_cases
> [  130.599140] kvm [4518]: nVHE hyp panic at: [<ffff800081102b58>] __kvm_nvhe___vgic_v3_restore_vmcr_aprs+0x8/0x84!
> [  130.603685] kvm [4518]: Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE
> [  130.611962] kvm [4518]: Hyp Offset: 0xfffeca95ed000000
> [  130.617053] Kernel panic - not syncing: HYP panic:

Thanks, fix posted here [*], although as a consequence this machine will
stop running KVM in protected mode (which was never meant to work in the
first place).

[*]: https://lore.kernel.org/kvmarm/20250203231543.233511-1-oliver.upton@linux.dev/

-- 
Thanks,
Oliver