kernel.git/arch/powerpc/kvm, branch linux-4.17.y

KVM: PPC: Check if IOMMU page is contained in the pinned physical page

2018-07-28T05:57:12Z

commit 76fa4975f3ed12d15762bc979ca44078598ed8ee upstream. A VM which has: - a DMA capable device passed through to it (eg. network card); - running a malicious kernel that ignores H_PUT_TCE failure; - capability of using IOMMU pages bigger that physical pages can create an IOMMU mapping that exposes (for example) 16MB of the host physical memory to the device when only 64K was allocated to the VM. The remaining 16MB - 64K will be some other content of host memory, possibly including pages of the VM, but also pages of host kernel memory, host programs or other VMs. The attacking VM does not control the location of the page it can map, and is only allowed to map as many pages as it has pages of RAM. We already have a check in drivers/vfio/vfio_iommu_spapr_tce.c that an IOMMU page is contained in the physical page so the PCI hardware won't get access to unassigned host memory; however this check is missing in the KVM fastpath (H_PUT_TCE accelerated code). We were lucky so far and did not hit this yet as the very first time when the mapping happens we do not have tbl::it_userspace allocated yet and fall back to the userspace which in turn calls VFIO IOMMU driver, this fails and the guest does not retry, This stores the smallest preregistered page size in the preregistered region descriptor and changes the mm_iommu_xxx API to check this against the IOMMU page size. This calculates maximum page size as a minimum of the natural region alignment and compound page size. For the page shift this uses the shift returned by find_linux_pte() which indicates how the page is mapped to the current userspace - if the page is huge and this is not a zero, then it is a leaf pte and the page is mapped within the range. Fixes: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Signed-off-by: Alexey Kardashevskiy Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book 3S HV: Do ptesync in radix guest exit path

2018-05-17T05:17:13Z

A radix guest can execute tlbie instructions to invalidate TLB entries. After a tlbie or a group of tlbies, it must then do the architected sequence eieio; tlbsync; ptesync to ensure that the TLB invalidation has been processed by all CPUs in the system before it can rely on no CPU using any translation that it just invalidated. In fact it is the ptesync which does the actual synchronization in this sequence, and hardware has a requirement that the ptesync must be executed on the same CPU thread as the tlbies which it is expected to order. Thus, if a vCPU gets moved from one physical CPU to another after it has done some tlbies but before it can get to do the ptesync, the ptesync will not have the desired effect when it is executed on the second physical CPU. To fix this, we do a ptesync in the exit path for radix guests. If there are any pending tlbies, this will wait for them to complete. If there aren't, then ptesync will just do the same as sync. Signed-off-by: Paul Mackerras

KVM: PPC: Book3S HV: XIVE: Resend re-routed interrupts on CPU priority change

2018-05-17T05:17:06Z

When a vcpu priority (CPPR) is set to a lower value (masking more interrupts), we stop processing interrupts already in the queue for the priorities that have now been masked. If those interrupts were previously re-routed to a different CPU, they might still be stuck until the older one that has them in its queue processes them. In the case of guest CPU unplug, that can be never. To address that without creating additional overhead for the normal interrupt processing path, this changes H_CPPR handling so that when such a priority change occurs, we scan the interrupt queue for that vCPU, and for any interrupt in there that has been re-routed, we replace it with a dummy and force a re-trigger. Signed-off-by: Benjamin Herrenschmidt Tested-by: Alexey Kardashevskiy Signed-off-by: Paul Mackerras

KVM: PPC: Book3S HV: Make radix clear pte when unmapping

2018-05-17T05:16:59Z

The current partition table unmap code clears the _PAGE_PRESENT bit out of the pte, which leaves pud_huge/pmd_huge true and does not clear pud_present/pmd_present. This can confuse subsequent page faults and possibly lead to the guest looping doing continual hypervisor page faults. Signed-off-by: Nicholas Piggin Signed-off-by: Paul Mackerras

KVM: PPC: Book3S HV: Make radix use correct tlbie sequence in kvmppc_radix_tlbie_page

2018-05-17T05:16:53Z

The standard eieio ; tlbsync ; ptesync must follow tlbie to ensure it is ordered with respect to subsequent operations. Signed-off-by: Nicholas Piggin Signed-off-by: Paul Mackerras

KVM: PPC: Book3S HV: Snapshot timebase offset on guest entry

2018-05-17T05:16:45Z

Currently, the HV KVM guest entry/exit code adds the timebase offset from the vcore struct to the timebase on guest entry, and subtracts it on guest exit. Which is fine, except that it is possible for userspace to change the offset using the SET_ONE_REG interface while the vcore is running, as there is only one timebase offset per vcore but potentially multiple VCPUs in the vcore. If that were to happen, KVM would subtract a different offset on guest exit from that which it had added on guest entry, leading to the timebase being out of sync between cores in the host, which then leads to bad things happening such as hangs and spurious watchdog timeouts. To fix this, we add a new field 'tb_offset_applied' to the vcore struct which stores the offset that is currently applied to the timebase. This value is set from the vcore tb_offset field on guest entry, and is what is subtracted from the timebase on guest exit. Since it is zero when the timebase offset is not applied, we can simplify the logic in kvmhv_start_timing and kvmhv_accumulate_time. In addition, we had secondary threads reading the timebase while running concurrently with code on the primary thread which would eventually add or subtract the timebase offset from the timebase. This occurred while saving or restoring the DEC register value on the secondary threads. Although no specific incorrect behaviour has been observed, this is a race which should be fixed. To fix it, we move the DEC saving code to just before we call kvmhv_commence_exit, and the DEC restoring code to after the point where we have waited for the primary thread to switch the MMU context and add the timebase offset. That way we are sure that the timebase contains the guest timebase value in both cases. Signed-off-by: Paul Mackerras

powerpc/kvm/booke: Fix altivec related build break

2018-04-27T06:36:03Z

Add missing "altivec unavailable" interrupt injection helper thus fixing the linker error below: arch/powerpc/kvm/emulate_loadstore.o: In function `kvmppc_check_altivec_disabled': arch/powerpc/kvm/emulate_loadstore.c: undefined reference to `.kvmppc_core_queue_vec_unavail' Fixes: 09f984961c137c4b ("KVM: PPC: Book3S: Add MMIO emulation for VMX instructions") Signed-off-by: Laurentiu Tudor Signed-off-by: Michael Ellerman

Merge tag 'powerpc-4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2018-04-15T18:57:12Z

Pull powerpc fixes from Michael Ellerman: - Fix crashes when loading modules built with a different CONFIG_RELOCATABLE value by adding CONFIG_RELOCATABLE to vermagic. - Fix busy loops in the OPAL NVRAM driver if we get certain error conditions from firmware. - Remove tlbie trace points from KVM code that's called in real mode, because it causes crashes. - Fix checkstops caused by invalid tlbiel on Power9 Radix. - Ensure the set of CPU features we "know" are always enabled is actually the minimal set when we build with support for firmware supplied CPU features. Thanks to: Aneesh Kumar K.V, Anshuman Khandual, Nicholas Piggin. * tag 'powerpc-4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s: Fix CPU_FTRS_ALWAYS vs DT CPU features powerpc/mm/radix: Fix checkstops caused by invalid tlbiel KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode powerpc/8xx: Fix build with hugetlbfs enabled powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops powerpc/fscr: Enable interrupts earlier before calling get_user() powerpc/64s: Fix section mismatch warnings from setup_rfi_flush() powerpc/modules: Fix crashes by adding CONFIG_RELOCATABLE to vermagic

KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode

2018-04-11T02:35:33Z

This crashes with a "Bad real address for load" attempting to load from the vmalloc region in realmode (faulting address is in DAR). Oops: Bad interrupt in KVM entry/exit code, sig: 6 [#1] LE SMP NR_CPUS=2048 NUMA PowerNV CPU: 53 PID: 6582 Comm: qemu-system-ppc Not tainted 4.16.0-01530-g43d1859f0994 NIP: c0000000000155ac LR: c0000000000c2430 CTR: c000000000015580 REGS: c000000fff76dd80 TRAP: 0200 Not tainted (4.16.0-01530-g43d1859f0994) MSR: 9000000000201003 CR: 48082222 XER: 00000000 CFAR: 0000000102900ef0 DAR: d00017fffd941a28 DSISR: 00000040 SOFTE: 3 NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0 LR [c0000000000c2430] do_tlbies+0x230/0x2f0 I suspect the reason is the per-cpu data is not in the linear chunk. This could be restored if that was able to be fixed, but for now, just remove the tracepoints. Fixes: 0428491cba92 ("powerpc/mm: Trace tlbie(l) instructions") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2018-04-09T18:42:31Z

Pull kvm updates from Paolo Bonzini: "ARM: - VHE optimizations - EL2 address space randomization - speculative execution mitigations ("variant 3a", aka execution past invalid privilege register access) - bugfixes and cleanups PPC: - improvements for the radix page fault handler for HV KVM on POWER9 s390: - more kvm stat counters - virtio gpu plumbing - documentation - facilities improvements x86: - support for VMware magic I/O port and pseudo-PMCs - AMD pause loop exiting - support for AMD core performance extensions - support for synchronous register access - expose nVMX capabilities to userspace - support for Hyper-V signaling via eventfd - use Enlightened VMCS when running on Hyper-V - allow userspace to disable MWAIT/HLT/PAUSE vmexits - usual roundup of optimizations and nested virtualization bugfixes Generic: - API selftest infrastructure (though the only tests are for x86 as of now)" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (174 commits) kvm: x86: fix a prototype warning kvm: selftests: add sync_regs_test kvm: selftests: add API testing infrastructure kvm: x86: fix a compile warning KVM: X86: Add Force Emulation Prefix for "emulate the next instruction" KVM: X86: Introduce handle_ud() KVM: vmx: unify adjacent #ifdefs x86: kvm: hide the unused 'cpu' variable KVM: VMX: remove bogus WARN_ON in handle_ept_misconfig Revert "KVM: X86: Fix SMRAM accessing even if VM is shutdown" kvm: Add emulation for movups/movupd KVM: VMX: raise internal error for exception during invalid protected mode state KVM: nVMX: Optimization: Dont set KVM_REQ_EVENT when VMExit with nested_run_pending KVM: nVMX: Require immediate-exit when event reinjected to L2 and L1 event pending KVM: x86: Fix misleading comments on handling pending exceptions KVM: x86: Rename interrupt.pending to interrupt.injected KVM: VMX: No need to clear pending NMI/interrupt on inject realmode interrupt x86/kvm: use Enlightened VMCS when running on Hyper-V x86/hyper-v: detect nested features x86/hyper-v: define struct hv_enlightened_vmcs and clean field bits ...