With the optimizations for TLB invalidation from commit 0cef77c7798a
("powerpc/64s/radix: flush remote CPUs out of single-threaded
mm_cpumask"), the scope of a TLBI (global vs. local) can now be
influenced by the value of the 'copros' counter of the memory context.
When calling mm_context_remove_copro(), the 'copros' counter is
decremented first before flushing. It may have the unintended side
effect of sending local TLBIs when we explicitly need global
invalidations in this case. Thus breaking any nMMU user in a bad and
unpredictable way.
Fix it by flushing first, before updating the 'copros' counter, so
that invalidations will be global.
Fixes: 0cef77c7798a ("powerpc/64s/radix: flush remote CPUs out of single-threaded mm_cpumask")
Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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 <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
added a call for pgtable_page_dtor in the rcu page table free routine. We missed
the fact that for 32 bit platforms we did call the 'dtor' early. Drop the extra
call for pgtable_page_dtor. We remove the call from __pte_free_tlb so that we
do the page table free and 'dtor' call together. This should help when we
switch these platforms to pte fragments.
Fixes: 667416f38554 ("powerpc/mm: Fix kernel crash on page table free")
Reported-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Wire up io_pgetevents system call on powerpc. io_pgetevents is a new syscall to read asynchronous I/O events from the completion queue. Tested with libaio branch aio-poll[1] and the io_pgetevents test (#22) passed on both ppc64 LE and BE modes. [1] https://pagure.io/libaio/branch/aio-poll CC: Christoph Hellwig <hch@lst.de> Signed-off-by: Breno Leitao <leitao@debian.org> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With 4k page size for hugetlb we allocate hugepage directories from its on slab
cache. With patch 0c4d26802 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
we missed to free these allocated hugepd tables.
Update pgtable_free to handle hugetlb hugepd directory table.
Fixes: 0c4d268029bf ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Add CONFIG_HUGETLB_PAGE guard to fix build break]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
I broke the build when CONFIG_NMI_IPI=n with my recent commit to add
arch_trigger_cpumask_backtrace(), eg:
stacktrace.c:(.text+0x1b0): undefined reference to `.smp_send_safe_nmi_ipi'
We should rework the CONFIG symbols here in future to avoid these
double barrelled ifdefs but for now they fix the build.
Fixes: 5cc05910f26e ("powerpc/64s: Wire up arch_trigger_cpumask_backtrace()")
Reported-by: Christophe LEROY <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull more Kbuild updates from Masahiro Yamada: - fix some bugs introduced by the recent Kconfig syntax extension - add some symbols about compiler information in Kconfig, such as CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc. - test compiler capability for the stack protector in Kconfig, and clean-up Makefile - test compiler capability for GCC-plugins in Kconfig, and clean-up Makefile - allow to enable GCC-plugins for COMPILE_TEST - test compiler capability for KCOV in Kconfig and correct dependency - remove auto-detect mode of the GCOV format, which is now more nicely handled in Kconfig - test compiler capability for mprofile-kernel on PowerPC, and clean-up Makefile - misc cleanups * tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify() kconfig: fix localmodconfig sh: remove no-op macro VMLINUX_SYMBOL() powerpc/kbuild: move -mprofile-kernel check to Kconfig Documentation: kconfig: add recommended way to describe compiler support gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST gcc-plugins: test plugin support in Kconfig and clean up Makefile gcc-plugins: move GCC version check for PowerPC to Kconfig kcov: test compiler capability in Kconfig and correct dependency gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig kconfig: add CC_IS_CLANG and CLANG_VERSION kconfig: add CC_IS_GCC and GCC_VERSION stack-protector: test compiler capability in Kconfig and drop AUTO mode kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE
This eliminates the workaround that requires disabling -mprofile-kernel by default in Kconfig. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull restartable sequence support from Thomas Gleixner: "The restartable sequences syscall (finally): After a lot of back and forth discussion and massive delays caused by the speculative distraction of maintainers, the core set of restartable sequences has finally reached a consensus. It comes with the basic non disputed core implementation along with support for arm, powerpc and x86 and a full set of selftests It was exposed to linux-next earlier this week, so it does not fully comply with the merge window requirements, but there is really no point to drag it out for yet another cycle" * 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rseq/selftests: Provide Makefile, scripts, gitignore rseq/selftests: Provide parametrized tests rseq/selftests: Provide basic percpu ops test rseq/selftests: Provide basic test rseq/selftests: Provide rseq library selftests/lib.mk: Introduce OVERRIDE_TARGETS powerpc: Wire up restartable sequences system call powerpc: Add syscall detection for restartable sequences powerpc: Add support for restartable sequences x86: Wire up restartable sequence system call x86: Add support for restartable sequences arm: Wire up restartable sequences system call arm: Add syscall detection for restartable sequences arm: Add restartable sequences support rseq: Introduce restartable sequences system call uapi/headers: Provide types_32_64.h