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[70.31.27.79]) by smtp.gmail.com with ESMTPSA id v4-20020a05622a014400b00343057845f7sm4477368qtw.20.2022.10.11.12.59.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Oct 2022 12:59:48 -0700 (PDT) From: Peter Xu To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: peterx@redhat.com, David Matlack , "Dr . David Alan Gilbert" , David Hildenbrand , John Hubbard , Andrew Morton , Linux MM Mailing List , Mike Kravetz , Paolo Bonzini , Andrea Arcangeli , Sean Christopherson Subject: [PATCH v4 4/4] kvm: x86: Allow to respond to generic signals during slow PF Date: Tue, 11 Oct 2022 15:59:47 -0400 Message-Id: <20221011195947.557281-1-peterx@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221011195809.557016-1-peterx@redhat.com> References: <20221011195809.557016-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Enable x86 slow page faults to be able to respond to non-fatal signals, returning -EINTR properly when it happens. Signed-off-by: Peter Xu Reviewed-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index cc26f425f41c..83b9c034313d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3148,8 +3148,13 @@ static void kvm_send_hwpoison_signal(unsigned long a= ddress, struct task_struct * send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk); } =20 -static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t= pfn) +static int kvm_handle_error_pfn(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_= t pfn) { + if (is_sigpending_pfn(pfn)) { + kvm_handle_signal_exit(vcpu); + return -EINTR; + } + /* * Do not cache the mmio info caused by writing the readonly gfn * into the spte otherwise read access on readonly gfn also can @@ -3171,7 +3176,7 @@ static int handle_abnormal_pfn(struct kvm_vcpu *vcpu,= struct kvm_page_fault *fau { /* The pfn is invalid, report the error! */ if (unlikely(is_error_pfn(fault->pfn))) - return kvm_handle_bad_page(vcpu, fault->gfn, fault->pfn); + return kvm_handle_error_pfn(vcpu, fault->gfn, fault->pfn); =20 if (unlikely(!fault->slot)) { gva_t gva =3D fault->is_tdp ? 0 : fault->addr; @@ -4186,7 +4191,12 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, st= ruct kvm_page_fault *fault) } } =20 - fault->pfn =3D __gfn_to_pfn_memslot(slot, fault->gfn, false, false, NULL, + /* + * Allow gup to bail on pending non-fatal signals when it's also allowed + * to wait for IO. Note, gup always bails if it is unable to quickly + * get a page and a fatal signal, i.e. SIGKILL, is pending. + */ + fault->pfn =3D __gfn_to_pfn_memslot(slot, fault->gfn, false, true, NULL, fault->write, &fault->map_writable, &fault->hva); return RET_PF_CONTINUE; --=20 2.37.3