From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7BD8AC433F5 for ; Thu, 9 Dec 2021 18:35:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=i5ot8pORBPSnO1ivjAXZ4Prnf+gF7M4bT/zhTHQ8itg=; b=47S7tqPnschkaY ryEjV4xgX9oMGkL2/y0QyHBL/ax4Qx1DMDN8xxs1GldsQRbbvL1zYG4XcgFI/YddizIlMr8qk8av5 yi4QhK1m+cEf4Hylu7ClaPz8nCs3nMSkhUf6PDJrEDkWkUkw48RQLk3lSQvoR/E/uTswvpksw2sNL UIJOKEOjZTISsY1o8anQ+qH/az5FH3JtCaoK5XdH7zIoDMfKN7yZdvWF4bD8CNUz4le8hNosKpW1S 1mxafMzgeyip6QBzLwJxiueckTvwxyBnnxrnJi+ppqg4ZX758T/OG0faU9vFuY2JNCGMlL74XMvSw 11Jb4r6xQqshN18Q3fQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mvOFF-00HEko-Kn; Thu, 09 Dec 2021 18:34:17 +0000 Received: from mail-ed1-x533.google.com ([2a00:1450:4864:20::533]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mvOFB-00HEjq-Jq; Thu, 09 Dec 2021 18:34:15 +0000 Received: by mail-ed1-x533.google.com with SMTP id l25so22642281eda.11; Thu, 09 Dec 2021 10:34:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=VmHNjKHHTgpu8LKf+wLbu6tr5d2B6TY5WNkaxl4rmr8=; b=gZq6Dj67kII8EQrFcvQRrysaXkPXfgaFl8h/21JGy/fEUeqdUxugDKnd0CNL1EUdHK KJPwK37d4PW840KmytVunGJapbLoZk4G3qw+TbDO8UYWUa2yu8kM7BqASqD3VbTbjPSr uYvvS+DgMUmrivsJTJ5U61ojewQPuA8oKfTgJidcMoKvKd75dFwAseVuJPPbufqS40gT sn9TuVUT5jgHVAMipF5b2yN0DSs3jGlOqB8UJmtZWNWcU0Bopi2mvXa3ytZ+oA/p2nkv P6BXBfcqsPMiZ2N//CV0MDTVNZrb5hlDan1lqFxK+s+uKW5LM3ou1RBnyIftv4h7SWPY xNxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:message-id:date:mime-version:user-agent :subject:content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=VmHNjKHHTgpu8LKf+wLbu6tr5d2B6TY5WNkaxl4rmr8=; b=yeaFIaq/bY3hNS4eYGpIk2Cmv9E6WoVXroprCQqL+oOxURMsHmqHB7RMAv+S1ozrHJ O2sPa8HHvI8T3AG+LfkVfihzxF6lEeGpiRCNZbRtbpsACtNyAUA1nbFK+mfa3IrUbbud RcPgcYh5MhoFxQci3AaoE5GEGBInZx0eWUComjQ0NR6wXcKprmFBWVfsTt0/pktNoQSy IeDdHjrYLSv+10fVoIQR2LjQrEp1NZvQ7Y6clBmxrv/joJgonPgaILYROQPJrsptBO0o reSe5Kv3449GuyC6HsCGkD+i/T+IiwxQC4AADOkWtYaTXccPVsfMTNsoMqut9GQIzExJ NjiQ== X-Gm-Message-State: AOAM532GGGsxTJO1BHQPOZ9e6oFSeRhPWJQDY6K2nba3Q+pGHJ4O2EOo /RxSCskZUMs338ho9KT2ksk= X-Google-Smtp-Source: ABdhPJzPr2JWAHHRiyW9tf+vJ9HDTL67K/LwoYescyr21dhuVB9iq2UisCXP0bQ++tHwzdvxo9UJXA== X-Received: by 2002:a17:906:f43:: with SMTP id h3mr17722168ejj.414.1639074851284; Thu, 09 Dec 2021 10:34:11 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.googlemail.com with ESMTPSA id yd20sm299781ejb.47.2021.12.09.10.34.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Dec 2021 10:34:10 -0800 (PST) Message-ID: Date: Thu, 9 Dec 2021 19:34:08 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v5 08/12] KVM: Reinstate gfn_to_pfn_cache with invalidation support Content-Language: en-US To: David Woodhouse , kvm Cc: Boris Ostrovsky , Joao Martins , "jmattson @ google . com" , "wanpengli @ tencent . com" , "seanjc @ google . com" , "vkuznets @ redhat . com" , "mtosatti @ redhat . com" , "joro @ 8bytes . org" , karahmed@amazon.com, Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Huacai Chen , Aleksandar Markovic , Michael Ellerman , Benjamin Herrenschmidt , Anup Patel , Christian Borntraeger , kvmarm@lists.cs.columbia.edu, linux-arm-kernel , linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-s390@vger.kernel.org, butt3rflyh4ck References: <20211121125451.9489-1-dwmw2@infradead.org> <20211121125451.9489-9-dwmw2@infradead.org> From: Paolo Bonzini In-Reply-To: <20211121125451.9489-9-dwmw2@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211209_103413_662990_20429BDC X-CRM114-Status: GOOD ( 17.62 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Sorry for the late review... On 11/21/21 13:54, David Woodhouse wrote: > +EXPORT_SYMBOL_GPL(kvm_gfn_to_pfn_cache_check); > + > +static void __release_gpc(struct kvm *kvm, kvm_pfn_t pfn, void *khva, > + gpa_t gpa, bool dirty) > +{ > + /* Unmap the old page if it was mapped before, and release it */ > + if (!is_error_noslot_pfn(pfn)) { > + if (khva) { > + if (pfn_valid(pfn)) > + kunmap(pfn_to_page(pfn)); > +#ifdef CONFIG_HAS_IOMEM > + else > + memunmap(khva); > +#endif > + } Considering that the khva is passed directly to memunmap, perhaps it's cleaner to ensure it's page-aligned: diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 13cae72d39e9..267477bd2972 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -147,7 +147,7 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, old_gpa = gpc->gpa; old_pfn = gpc->pfn; - old_khva = gpc->khva; + old_khva = (void *)((unsigned long)gpc->khva & ~PAGE_MASK); old_uhva = gpc->uhva; old_valid = gpc->valid; old_dirty = gpc->dirty; @@ -209,7 +209,7 @@ int kvm_gfn_to_pfn_cache_refresh(struct kvm *kvm, struct gfn_to_pfn_cache *gpc, if (gpc->kernel_map) { if (new_pfn == old_pfn) { - new_khva = (void *)((unsigned long)old_khva - page_offset); + new_khva = old_khva; old_pfn = KVM_PFN_ERR_FAULT; old_khva = NULL; } else if (pfn_valid(new_pfn)) { @@ -265,7 +265,7 @@ void kvm_gfn_to_pfn_cache_unmap(struct kvm *kvm, struct gfn_to_pfn_cache *gpc) gpc->valid = false; - old_khva = gpc->khva; + old_khva = (void *)((unsigned long)gpc->khva & ~PAGE_MASK); old_dirty = gpc->dirty; old_gpa = gpc->gpa; old_pfn = gpc->pfn; > > + retry_map: > + mmu_seq = kvm->mmu_notifier_seq; > + smp_rmb(); > + > + /* We always request a writeable mapping */ > + new_pfn = hva_to_pfn(uhva, false, NULL, true, NULL); > + if (is_error_noslot_pfn(new_pfn)) { > + ret = -EFAULT; > + goto map_done; > + } > + > + KVM_MMU_READ_LOCK(kvm); > + retry = mmu_notifier_retry_hva(kvm, mmu_seq, uhva); > + KVM_MMU_READ_UNLOCK(kvm); > + if (retry) { > + cond_resched(); > + goto retry_map; > + } > + This should also be a separate function, like static kvm_pfn_t hva_to_pfn_retry(unsigned long uhva) { kvm_pfn_t new_pfn unsigned long mmu_seq; int retry; retry_map: mmu_seq = kvm->mmu_notifier_seq; smp_rmb(); /* We always request a writeable mapping */ new_pfn = hva_to_pfn(uhva, false, NULL, true, NULL); if (is_error_noslot_pfn(new_pfn)) return new_pfn; KVM_MMU_READ_LOCK(kvm); retry = mmu_notifier_retry_hva(kvm, mmu_seq, uhva); KVM_MMU_READ_UNLOCK(kvm); if (retry) { cond_resched(); goto retry_map; } return new_pfn; } > > + write_lock_irq(&gpc->lock); > + if (ret) { > + gpc->valid = false; > + gpc->pfn = KVM_PFN_ERR_FAULT; > + gpc->khva = NULL; > + } else { > + /* At this point, gpc->valid may already have been cleared */ > + gpc->pfn = new_pfn; > + gpc->khva = new_khva + page_offset; > + } Should set gpc->khva only if new_khva != NULL (i.e. only if gpc->kernel_map is true). Paolo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel