From: "Huang, Kai" <kai.huang@intel.com>
To: "seanjc@google.com" <seanjc@google.com>,
"nicoyip.dev@gmail.com" <nicoyip.dev@gmail.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"bp@alien8.de" <bp@alien8.de>, "x86@kernel.org" <x86@kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"Zhao, Yan Y" <yan.y.zhao@intel.com>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"tglx@kernel.org" <tglx@kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: x86/mmu: Protect noncoherent DMA zaps with SRCU
Date: Mon, 24 Aug 2026 21:36:13 +0000 [thread overview]
Message-ID: <303eb59af516335e288647c19254928f89fa833a.camel@intel.com> (raw)
In-Reply-To: <aoyEMBz-SYLigbGp@google.com>
On Mon, 2026-08-24 at 10:49 -0700, Sean Christopherson wrote:
> Alternatively, what if we have kvm_zap_gfn_range() acquire SRCU? Nesting "locks"
> is a-ok, and two of the three users of kvm_zap_gfn_range() have had this bug (see
> commit 074c00800719 ("KVM: x86: Use SRCU to protect zap in
> __kvm_set_or_clear_apicv_inhibit()").
kvm_vcpu_srcu_read_lock() doesn't allow nesting lock of KVM's SRCU. Doesn't
seem to be a problem for this particular case, though, because
sev_handle_rmp_fault() calls kvm_zap_gfn_range() after kvm_vcpu_srcu_read_lock()
is called.
next prev parent reply other threads:[~2026-08-24 21:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-22 19:02 [PATCH] KVM: x86/mmu: Protect noncoherent DMA zaps with SRCU Chengfeng Ye
2026-08-24 9:50 ` Huang, Kai
2026-08-24 17:49 ` Sean Christopherson
2026-08-24 21:36 ` Huang, Kai [this message]
2026-08-24 21:49 ` Sean Christopherson
2026-08-24 22:15 ` Huang, Kai
2026-08-25 18:40 ` Chengfeng Ye
2026-08-25 18:39 ` [PATCH v2] KVM: x86: Take SRCU in kvm_zap_gfn_range() Chengfeng Ye
2026-08-26 0:13 ` Huang, Kai
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