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Tue, 09 Jun 2026 04:31:44 -0700 (PDT) Date: Tue, 9 Jun 2026 20:31:41 +0900 From: Hyunwoo Kim To: Marc Zyngier Cc: gregkh@linuxfoundation.org, stable@vger.kernel.org, oupton@kernel.org, imv4bel@gmail.com Subject: Re: [PATCH 6.12.y] KVM: arm64: Take the SRCU lock for page table walks in fault injection and AT emulation Message-ID: References: <86fr2wt34q.wl-maz@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86fr2wt34q.wl-maz@kernel.org> On Tue, Jun 09, 2026 at 11:33:09AM +0100, Marc Zyngier wrote: > On Tue, 09 Jun 2026 11:13:36 +0100, > Hyunwoo Kim wrote: > > > > [ Upstream commit f2ca45b50d4216c9cc7ffabf50d9ad1932209251 ] > > > > walk_s1() and kvm_walk_nested_s2() expect to be called while holding > > kvm->srcu to guard against memslot changes. While this is generally > > the case, __kvm_at_s12() and __kvm_find_s1_desc_level() call into the > > respective walkers without taking kvm->srcu. > > > > Fix by acquiring kvm->srcu prior to the table walk in both instances. > > > > Cc: stable@vger.kernel.org > > Fixes: 50f77dc87f13 ("KVM: arm64: Populate level on S1PTW SEA injection") > > Fixes: be04cebf3e78 ("KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W}") > > Suggested-by: Oliver Upton > > Signed-off-by: Hyunwoo Kim > > Reviewed-by: Oliver Upton > > Link: https://patch.msgid.link/aiAZfdeyanIvP8SD@v4bel > > Signed-off-by: Marc Zyngier > > [ Hyunwoo Kim: __kvm_at_s12() returns void in 6.12.y, so the context > > differs from upstream (return; instead of return ret;). The > > __kvm_find_s1_desc_level() hunk (Fixes: 50f77dc87f13) is dropped, as > > that function is v6.18+ and absent here; only the __kvm_at_s12() / > > kvm_walk_nested_s2() change (Fixes: be04cebf3e78) applies. ] > > Signed-off-by: Hyunwoo Kim > > I don't think this is necessary. 6.12 doesn't actually have NV support > (it was enabled only from userspace in 6.17), therefore the ATS12 > emulation isn't reachable. Ah, I see. Thank you for the review. > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible. Best regards, Hyunwoo Kim