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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id d6-20020a170902cec600b00176a715653dsm268651plg.145.2022.10.06.18.39.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Oct 2022 18:39:25 -0700 (PDT) Date: Fri, 7 Oct 2022 01:39:17 +0000 From: Sean Christopherson To: Peter Xu Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, David Hildenbrand , Andrew Morton , Andrea Arcangeli , Paolo Bonzini , "Dr . David Alan Gilbert" , Linux MM Mailing List , John Hubbard Subject: Re: [PATCH v3 2/3] kvm: Add new pfn error KVM_PFN_ERR_SIGPENDING Message-ID: References: <20220817003614.58900-1-peterx@redhat.com> <20220817003614.58900-3-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220817003614.58900-3-peterx@redhat.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1665106770; a=rsa-sha256; cv=none; b=zPA0vT+GSu7HSG2zKqbuW8OftdZqPePjbTw0gzXPkrXEK0UCM315prpRAPflCa8pryh9HV wNA6BIdCox43I+F1Dxmq//hERV9gtAhpvm/9Md3ORnWNbnQcjOEv4HQ9iolu7dlLzLvf9P zPomo8S9CUxzvL5tYpFO6zAYduz+kgY= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=cmiwTKlV; spf=pass (imf09.hostedemail.com: domain of seanjc@google.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=seanjc@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1665106770; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VgARxyE2xUeWs6ZD9Z2C3jeaxK0tUIpvYnHYcRwlYa0=; b=edx/seR0/R9nK7lg2Fxc5vUJvuiNIm+uHF0O5glfnvDaI6OaWKE/69Z6jNbptNK2+7TlIZ 7oJKbApDilbt9umnjrzwDdhKeZtZyieP4ijcPNsP39WbHfcSsbXhESKXM+4p7OqTrdHc8F xYtVAol7BsWWDrDP3BSVIkB//2JLxPA= X-Rspamd-Queue-Id: 9749414000B X-Rspam-User: Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=cmiwTKlV; spf=pass (imf09.hostedemail.com: domain of seanjc@google.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=seanjc@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: njdts9d35afgnbccmfagp7twcr3reak8 X-Rspamd-Server: rspam04 X-HE-Tag: 1665106770-534149 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 16, 2022, Peter Xu wrote: > Since at it, renaming kvm_handle_bad_page to kvm_handle_error_pfn assuming Please put parantheses after function names, e.g. kvm_handle_bad_page(). > that'll match better with what it does, e.g. KVM_PFN_ERR_SIGPENDING is not > accurately a bad page but just one kind of errors. ... > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 3e1317325e1f..23dc46da2f18 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3134,8 +3134,13 @@ static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct * > send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, PAGE_SHIFT, tsk); > } > > -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; > + } ... > @@ -2648,9 +2651,12 @@ kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async, > if (atomic) > return KVM_PFN_ERR_FAULT; > > - npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn); > + npages = hva_to_pfn_slow(addr, async, write_fault, interruptible, > + writable, &pfn); > if (npages == 1) > return pfn; > + if (npages == -EINTR) > + return KVM_PFN_ERR_SIGPENDING; This patch should be split into 3 parts: 1. Add KVM_PFN_ERR_SIGPENDING and the above code 2. Add the interruptible flag 3. Add handling in x86 and rename kvm_handle_bad_page() With #3 merged with patch 3. That was if there's oddball arch code that reacts poorly to KVM_PFN_ERR_SIGPENDING, those errors will bisect to #1. And if there's a typo in the plumbing, that bisects to #2. And if something goes sideways in x86, those bugs bisect to #3 (patch 3), and it's easy to revert just the x86 changes (though I can't imagine that's likely).