From: Gal Pressman <gal@nvidia.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Naveen N Rao <naveen@kernel.org>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: Gal Pressman <gal@nvidia.com>
Subject: [PATCH v2 0/2] KVM: x86: Fix UBSAN bool warnings in module parameters
Date: Wed, 25 Feb 2026 16:50:48 +0200 [thread overview]
Message-ID: <20260225145050.2350278-1-gal@nvidia.com> (raw)
Several KVM module parameters use int to support a special -1 (auto)
value, but rely on param_get_bool() for the sysfs getter.
When userspace reads these parameters before the auto value is resolved,
param_get_bool() interprets the int as a bool, triggering UBSAN "load of
value 255 is not a valid value for type '_Bool'" warnings.
Fix both instances by implementing getter functions that handle the -1
case before falling through to param_get_bool().
Changelog -
v1->v2: https://lore.kernel.org/all/20260210064621.1902269-1-gal@nvidia.com/
* Show auto avic as 'N' (Naveen)
Gal Pressman (2):
KVM: SVM: Fix UBSAN warning when reading avic parameter
KVM: x86/mmu: Fix UBSAN warning when reading nx_huge_pages parameter
arch/x86/kvm/mmu/mmu.c | 5 +++++
arch/x86/kvm/svm/avic.c | 13 ++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
--
2.52.0
next reply other threads:[~2026-02-25 14:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 14:50 Gal Pressman [this message]
2026-02-25 14:50 ` [PATCH v2 1/2] KVM: SVM: Fix UBSAN warning when reading avic parameter Gal Pressman
2026-02-26 5:35 ` Naveen N Rao
2026-02-25 14:50 ` [PATCH v2 2/2] KVM: x86/mmu: Fix UBSAN warning when reading nx_huge_pages parameter Gal Pressman
2026-03-05 17:08 ` [PATCH v2 0/2] KVM: x86: Fix UBSAN bool warnings in module parameters Sean Christopherson
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