From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58009 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945959AbcHRJrE (ORCPT ); Thu, 18 Aug 2016 05:47:04 -0400 Subject: Patch "[PATCH BACKPORT 3.10-3.15 1/4] MIPS: KVM: Fix mapped fault broken commpage handling" has been added to the 3.14-stable tree To: james.hogan@imgtec.com, gregkh@linuxfoundation.org, kvm@vger.kernel.org, linux-mips@linux-mips.org, pbonzini@redhat.com, ralf@linux-mips.org, rkrcmar@redhat.com, stable@vger.kernel.org Cc: , From: Date: Thu, 18 Aug 2016 11:47:01 +0200 In-Reply-To: <4980f95f6ec938cc80bb79c06222c535564a521d.1471021142.git-series.james.hogan@imgtec.com> Message-ID: <14715136211266@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled [PATCH BACKPORT 3.10-3.15 1/4] MIPS: KVM: Fix mapped fault broken commpage handling to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-kvm-fix-mapped-fault-broken-commpage-handling.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From james.hogan@imgtec.com Thu Aug 18 11:46:11 2016 From: James Hogan Date: Thu, 18 Aug 2016 10:22:52 +0100 Subject: [PATCH BACKPORT 3.10-3.15 1/4] MIPS: KVM: Fix mapped fault broken commpage handling To: Cc: James Hogan , Paolo Bonzini , Radim Krčmář , Ralf Baechle , , Message-ID: <4980f95f6ec938cc80bb79c06222c535564a521d.1471021142.git-series.james.hogan@imgtec.com> From: James Hogan commit c604cffa93478f8888bec62b23d6073dad03d43a upstream. kvm_mips_handle_mapped_seg_tlb_fault() appears to map the guest page at virtual address 0 to PFN 0 if the guest has created its own mapping there. The intention is unclear, but it may have been an attempt to protect the zero page from being mapped to anything but the comm page in code paths you wouldn't expect from genuine commpage accesses (guest kernel mode cache instructions on that address, hitting trapping instructions when executing from that address with a coincidental TLB eviction during the KVM handling, and guest user mode accesses to that address). Fix this to check for mappings exactly at KVM_GUEST_COMMPAGE_ADDR (it may not be at address 0 since commit 42aa12e74e91 ("MIPS: KVM: Move commpage so 0x0 is unmapped")), and set the corresponding EntryLo to be interpreted as 0 (invalid). Fixes: 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.") Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Radim Krčmář [james.hogan@imgtec.com: Backport to v3.10.y - v3.15.y] Signed-off-by: James Hogan Signed-off-by: Greg Kroah-Hartman --- arch/mips/kvm/kvm_tlb.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) --- a/arch/mips/kvm/kvm_tlb.c +++ b/arch/mips/kvm/kvm_tlb.c @@ -370,21 +370,27 @@ kvm_mips_handle_mapped_seg_tlb_fault(str unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0; struct kvm *kvm = vcpu->kvm; pfn_t pfn0, pfn1; + long tlb_lo[2]; + tlb_lo[0] = tlb->tlb_lo0; + tlb_lo[1] = tlb->tlb_lo1; - if ((tlb->tlb_hi & VPN2_MASK) == 0) { - pfn0 = 0; - pfn1 = 0; - } else { - if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo0) >> PAGE_SHIFT) < 0) - return -1; - - if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo1) >> PAGE_SHIFT) < 0) - return -1; - - pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo0) >> PAGE_SHIFT]; - pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo1) >> PAGE_SHIFT]; - } + /* + * The commpage address must not be mapped to anything else if the guest + * TLB contains entries nearby, or commpage accesses will break. + */ + if (!((tlb->tlb_hi ^ KVM_GUEST_COMMPAGE_ADDR) & + VPN2_MASK & (PAGE_MASK << 1))) + tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0; + + if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT) < 0) + return -1; + + if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT) < 0) + return -1; + + pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT]; + pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT]; if (hpa0) *hpa0 = pfn0 << PAGE_SHIFT; @@ -396,9 +402,9 @@ kvm_mips_handle_mapped_seg_tlb_fault(str entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ? kvm_mips_get_kernel_asid(vcpu) : kvm_mips_get_user_asid(vcpu)); entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) | (0x3 << 3) | - (tlb->tlb_lo0 & MIPS3_PG_D) | (tlb->tlb_lo0 & MIPS3_PG_V); + (tlb_lo[0] & MIPS3_PG_D) | (tlb_lo[0] & MIPS3_PG_V); entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) | (0x3 << 3) | - (tlb->tlb_lo1 & MIPS3_PG_D) | (tlb->tlb_lo1 & MIPS3_PG_V); + (tlb_lo[1] & MIPS3_PG_D) | (tlb_lo[1] & MIPS3_PG_V); #ifdef DEBUG kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc, Patches currently in stable-queue which might be from james.hogan@imgtec.com are queue-3.14/mips-kvm-add-missing-gfn-range-check.patch queue-3.14/mips-kvm-propagate-kseg0-mapped-tlb-fault-errors.patch queue-3.14/mips-kvm-fix-mapped-fault-broken-commpage-handling.patch queue-3.14/mips-kvm-fix-gfn-range-check-in-kseg0-tlb-faults.patch