From patchwork Thu Dec 12 17:28:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11288843 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 68A31138C for ; Thu, 12 Dec 2019 17:28:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 480F02173E for ; Thu, 12 Dec 2019 17:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576171735; bh=XeU0cSs24ITDRlPm2x/iNQaRz7R0Eudi/wDymSbqgi8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dBJe92SSKJ2zgAg1pxYhlbO/1Dd68hN3g0ziFc6cfh1J0RlTbPZwdATEwGmZ6zcZQ YtkMujfg9RVBeG/7bJlLBYZEMNbjDp1Se9I6UXr392+etf5/43nYJlmBCPmoD+B24h FpAyRtw8oS7CJfMvNNrFMYxrw4GDeKWJItRPU26s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730186AbfLLR2y (ORCPT ); Thu, 12 Dec 2019 12:28:54 -0500 Received: from inca-roads.misterjones.org ([213.251.177.50]:47471 "EHLO inca-roads.misterjones.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730177AbfLLR2w (ORCPT ); Thu, 12 Dec 2019 12:28:52 -0500 Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by cheepnis.misterjones.org with esmtpsa (TLSv1.2:DHE-RSA-AES128-GCM-SHA256:128) (Exim 4.80) (envelope-from ) id 1ifSGb-00069s-Dd; Thu, 12 Dec 2019 18:28:45 +0100 From: Marc Zyngier To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: Alexandru Elisei , Ard Biesheuvel , Christoffer Dall , Eric Auger , James Morse , Jia He , Mark Rutland , Miaohe Lin , Steven Price , Will Deacon , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Julien Thierry , Suzuki K Poulose , stable@vger.kernel.org Subject: [PATCH 8/8] KVM: arm/arm64: Properly handle faulting of device mappings Date: Thu, 12 Dec 2019 17:28:24 +0000 Message-Id: <20191212172824.11523-9-maz@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191212172824.11523-1-maz@kernel.org> References: <20191212172824.11523-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, rkrcmar@redhat.com, alexandru.elisei@arm.com, ard.biesheuvel@linaro.org, christoffer.dall@arm.com, eric.auger@redhat.com, james.morse@arm.com, justin.he@arm.com, mark.rutland@arm.com, linmiaohe@huawei.com, steven.price@arm.com, will@kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, stable@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org A device mapping is normally always mapped at Stage-2, since there is very little gain in having it faulted in. Nonetheless, it is possible to end-up in a situation where the device mapping has been removed from Stage-2 (userspace munmaped the VFIO region, and the MMU notifier did its job), but present in a userspace mapping (userpace has mapped it back at the same address). In such a situation, the device mapping will be demand-paged as the guest performs memory accesses. This requires to be careful when dealing with mapping size, cache management, and to handle potential execution of a device mapping. Reported-by: Alexandru Elisei Signed-off-by: Marc Zyngier Tested-by: Alexandru Elisei Reviewed-by: James Morse Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20191211165651.7889-2-maz@kernel.org --- virt/kvm/arm/mmu.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index a48994af70b8..0b32a904a1bb 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -38,6 +38,11 @@ static unsigned long io_map_base; #define KVM_S2PTE_FLAG_IS_IOMAP (1UL << 0) #define KVM_S2_FLAG_LOGGING_ACTIVE (1UL << 1) +static bool is_iomap(unsigned long flags) +{ + return flags & KVM_S2PTE_FLAG_IS_IOMAP; +} + static bool memslot_is_logging(struct kvm_memory_slot *memslot) { return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY); @@ -1698,6 +1703,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, vma_pagesize = vma_kernel_pagesize(vma); if (logging_active || + (vma->vm_flags & VM_PFNMAP) || !fault_supports_stage2_huge_mapping(memslot, hva, vma_pagesize)) { force_pte = true; vma_pagesize = PAGE_SIZE; @@ -1760,6 +1766,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, writable = false; } + if (exec_fault && is_iomap(flags)) + return -ENOEXEC; + spin_lock(&kvm->mmu_lock); if (mmu_notifier_retry(kvm, mmu_seq)) goto out_unlock; @@ -1781,7 +1790,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (writable) kvm_set_pfn_dirty(pfn); - if (fault_status != FSC_PERM) + if (fault_status != FSC_PERM && !is_iomap(flags)) clean_dcache_guest_page(pfn, vma_pagesize); if (exec_fault) @@ -1948,9 +1957,8 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) if (kvm_is_error_hva(hva) || (write_fault && !writable)) { if (is_iabt) { /* Prefetch Abort on I/O address */ - kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu)); - ret = 1; - goto out_unlock; + ret = -ENOEXEC; + goto out; } /* @@ -1992,6 +2000,11 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status); if (ret == 0) ret = 1; +out: + if (ret == -ENOEXEC) { + kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu)); + ret = 1; + } out_unlock: srcu_read_unlock(&vcpu->kvm->srcu, idx); return ret;