# git rev-parse -q --verify 76fa4975f3ed12d15762bc979ca44078598ed8ee^{commit} # git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test # git rev-parse -q --verify 76fa4975f3ed12d15762bc979ca44078598ed8ee^{commit} 76fa4975f3ed12d15762bc979ca44078598ed8ee # git checkout -q -f -B kisskb 76fa4975f3ed12d15762bc979ca44078598ed8ee # git clean -qxdf # < git log -1 # commit 76fa4975f3ed12d15762bc979ca44078598ed8ee # Author: Alexey Kardashevskiy # Date: Tue Jul 17 17:19:13 2018 +1000 # # KVM: PPC: Check if IOMMU page is contained in the pinned physical page # # 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 # < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version # < git log --format=%s --max-count=1 76fa4975f3ed12d15762bc979ca44078598ed8ee # < make -s -j 20 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux- x86_64_defconfig # make -s -j 20 ARCH=x86 O=/kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux- /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. /kisskb/src/arch/x86/kernel/apic/io_apic.c: In function 'mp_map_pin_to_irq': /kisskb/src/arch/x86/kernel/apic/io_apic.c:1033:6: warning: 'irq' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/kernel/cgroup/cgroup-v1.c: In function 'cgroup1_mount': /kisskb/src/kernel/cgroup/cgroup-v1.c:1256:20: warning: 'root' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/mm/vmstat.c: In function 'sysctl_vm_numa_stat_handler': /kisskb/src/mm/vmstat.c:89:5: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/Makefile:24: CC cannot link executables. Skipping bpfilter. kernel/rcu/tree.o: warning: objtool: rcu_init()+0x1c5: unreachable instruction /kisskb/src/arch/x86/kernel/e820.c: In function 'e820__setup_pci_gap': /kisskb/src/arch/x86/kernel/e820.c:653:2: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] kernel/trace/trace.o: warning: objtool: tracing_start()+0x6d: unreachable instruction /kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page': /kisskb/src/mm/hugetlb.c:1433:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/sound/hda/hdac_regmap.c: In function 'hda_reg_write': /kisskb/src/sound/hda/hdac_regmap.c:282:16: warning: 'err' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read': /kisskb/src/drivers/base/regmap/regmap.c:2497:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c: In function 'proc_reg_open': /kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c:339:21: note: 'pdeo' was declared here /kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write': /kisskb/src/drivers/base/regmap/regmap.c:1819:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/mac80211/mlme.c: In function 'ieee80211_rx_mgmt_beacon': /kisskb/src/net/mac80211/mlme.c:1353:3: warning: 'pwr_level_cisco' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/net/mac80211/mlme.c:1310:6: note: 'pwr_level_cisco' was declared here drivers/clk/clk.o: warning: objtool: clk_prepare_unlock()+0x44: unreachable instruction fs/aio.o: warning: objtool: aio_nr_sub()+0x2d: unreachable instruction /kisskb/src/drivers/dma-buf/reservation.c: In function 'reservation_object_add_shared_fence': /kisskb/src/drivers/dma-buf/reservation.c:207:2: warning: 'k' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/dma-buf/reservation.c:160:17: note: 'k' was declared here Completed OK # rm -rf /kisskb/build/powerpc-fixes_x86_64_defconfig_x86_64 # Build took: 0:01:43.251472