In protected nVHE mode, the host cannot access private owned hypervisor
memory. Also the hypervisor aims to remains simple to reduce the attack
surface and does not provide any printk support.
For the above reasons, the approach taken to provide hypervisor stacktraces
in protected mode is:
1) Unwind and save the hyp stack addresses in EL2 to a shared buffer
with the host (done in this patch).
2) Delegate the dumping and symbolization of the addresses to the
host in EL1 (later patch in the series).
On hyp_panic(), the hypervisor prepares the stacktrace before returning to
the host.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-16-kaleshsingh@google.com
Add some stub implementations of protected nVHE stack unwinder, for
building. These are implemented later in this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-15-kaleshsingh@google.com
In protected nVHE mode the host cannot directly access
hypervisor memory, so we will dump the hypervisor stacktrace
to a shared buffer with the host.
The minimum size for the buffer required, assuming the min frame
size of [x29, x30] (2 * sizeof(long)), is half the combined size of
the hypervisor and overflow stacks plus an additional entry to
delimit the end of the stacktrace.
The stacktrace buffers are used later in the series to dump the
nVHE hypervisor stacktrace when using protected-mode.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-14-kaleshsingh@google.com
This can be used to disable stacktrace for the protected KVM
nVHE hypervisor, in order to save on the associated memory usage.
This option is disabled by default, since protected KVM is not widely
used on platforms other than Android currently.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-13-kaleshsingh@google.com
Implements the common framework necessary for unwind() to work
for non-protected nVHE mode:
- on_accessible_stack()
- on_overflow_stack()
- unwind_next()
Non-protected nVHE unwind() is used to unwind and dump the hypervisor
stacktrace by the host in EL1
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-11-kaleshsingh@google.com
In non-protected nVHE mode (non-pKVM) the host can directly access
hypervisor memory; and unwinding of the hypervisor stacktrace is
done from EL1 to save on memory for shared buffers.
To unwind the hypervisor stack from EL1 the host needs to know the
starting point for the unwind and information that will allow it to
translate hypervisor stack addresses to the corresponding kernel
addresses. This patch sets up this book keeping. It is made use of
later in the series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-10-kaleshsingh@google.com
Add stub implementations of non-protected nVHE stack unwinder, for
building. These are implemented later in this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-9-kaleshsingh@google.com
On hyp stack overflow switch to 16-byte aligned secondary stack.
This provides us stack space to better handle overflows; and is
used in a subsequent patch to dump the hypervisor stacktrace.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-8-kaleshsingh@google.com
Add brief description on how to use stacktrace/common.h to implement
a stack unwinder.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-7-kaleshsingh@google.com
Move unwind() to stacktrace/common.h, and as a result
the kernel unwind_next() to asm/stacktrace.h. This allow
reusing unwind() in the implementation of the nVHE HYP
stack unwinder, later in the series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-6-kaleshsingh@google.com
The unwinder code is made reusable so that it can be used to
unwind various types of stacks. One usecase is unwinding the
nVHE hyp stack from the host (EL1) in non-protected mode. This
means that the unwinder must be able to translate HYP stack
addresses to kernel addresses.
Add a callback (stack_trace_translate_fp_fn) to allow specifying
the translation function.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-5-kaleshsingh@google.com
Move common unwind_next logic to stacktrace/common.h. This allows
reusing the code in the implementation the nVHE hypervisor stack
unwinder, later in this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-4-kaleshsingh@google.com
Move common on_accessible_stack checks to stacktrace/common.h. This is
used in the implementation of the nVHE hypervisor unwinder later in
this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-3-kaleshsingh@google.com
In order to reuse the arm64 stack unwinding logic for the nVHE
hypervisor stack, move the common code to a shared header
(arch/arm64/include/asm/stacktrace/common.h).
The nVHE hypervisor cannot safely link against kernel code, so we
make use of the shared header to avoid duplicated logic later in
this series.
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-2-kaleshsingh@google.com
Copy the task argument passed to arch_stack_walk() to unwind_state so that
it can be passed to unwind functions via unwind_state rather than as a
separate argument. The task is a fundamental part of the unwind state.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220617180219.20352-3-madvenka@linux.microsoft.com
Signed-off-by: Will Deacon <will@kernel.org>
unwind_init() is currently a single function that initializes all of the
unwind state. Split it into the following functions and call them
appropriately:
- unwind_init_from_regs() - initialize from regs passed by caller.
- unwind_init_from_caller() - initialize for the current task
from the caller of arch_stack_walk().
- unwind_init_from_task() - initialize from the saved state of a
task other than the current task. In this case, the other
task must not be running.
This is done for two reasons:
- the different ways of initializing are clear
- specialized code can be added to each initializer in the future.
Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220617180219.20352-2-madvenka@linux.microsoft.com
Signed-off-by: Will Deacon <will@kernel.org>
Use the non-atomic version of set_bit() in arch/arm64/kernel/stacktrace.c,
as there is no concurrent accesses to frame->prev_type.
This speeds up stack trace collection and improves the boot time of
Generic KASAN by 2-5%.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/23dfa36d1cc91e4a1059945b7834eac22fb9854d.1653317461.git.andreyknvl@google.com
Signed-off-by: Will Deacon <will@kernel.org>
Disable KASAN instrumentation of arch/arm64/kernel/stacktrace.c.
This speeds up Generic KASAN by 5-20%.
As a side-effect, KASAN is now unable to detect bugs in the stack trace
collection code. This is taken as an acceptable downside.
Also replace READ_ONCE_NOCHECK() with READ_ONCE() in stacktrace.c.
As the file is now not instrumented, there is no need to use the
NOCHECK version of READ_ONCE().
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/c4c944a2a905e949760fbeb29258185087171708.1653317461.git.andreyknvl@google.com
Signed-off-by: Will Deacon <will@kernel.org>
- Revert the moving of the jump labels initialisation before
setup_machine_fdt(). The bug was fixed in drivers/char/random.c.
- Ftrace fixes: branch range check and consistent handling of PLTs.
- Clean rather than invalidate FROM_DEVICE buffers at start of DMA
transfer (safer if such buffer is mapped in user space). A cache
invalidation is done already at the end of the transfer.
- A couple of clean-ups (unexport symbol, remove unused label).
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- Revert the moving of the jump labels initialisation before
setup_machine_fdt(). The bug was fixed in drivers/char/random.c.
- Ftrace fixes: branch range check and consistent handling of PLTs.
- Clean rather than invalidate FROM_DEVICE buffers at start of DMA
transfer (safer if such buffer is mapped in user space). A cache
invalidation is done already at the end of the transfer.
- A couple of clean-ups (unexport symbol, remove unused label).
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer
arm64/cpufeature: Unexport set_cpu_feature()
arm64: ftrace: remove redundant label
arm64: ftrace: consistently handle PLTs.
arm64: ftrace: fix branch range checks
Revert "arm64: Initialize jump labels before setup_machine_fdt()"
Invalidating the buffer memory in arch_sync_dma_for_device() for
FROM_DEVICE transfers
When using the streaming DMA API to map a buffer prior to inbound
non-coherent DMA (i.e. DMA_FROM_DEVICE), we invalidate any dirty CPU
cachelines so that they will not be written back during the transfer and
corrupt the buffer contents written by the DMA. This, however, poses two
potential problems:
(1) If the DMA transfer does not write to every byte in the buffer,
then the unwritten bytes will contain stale data once the transfer
has completed.
(2) If the buffer has a virtual alias in userspace, then stale data
may be visible via this alias during the period between performing
the cache invalidation and the DMA writes landing in memory.
Address both of these issues by cleaning (aka writing-back) the dirty
lines in arch_sync_dma_for_device(DMA_FROM_DEVICE) instead of discarding
them using invalidation.
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220606152150.GA31568@willie-the-truck
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220610151228.4562-2-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We currently export set_cpu_feature() to modules but there are no in tree
users that can be built as modules and it is hard to see cases where it
would make sense for there to be any such users. Remove the export to avoid
anyone else having to worry about why it is there and ensure that any users
that do get added get a bit more visiblity.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220615191504.626604-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Since commit:
c4a0ebf87c ("arm64/ftrace: Make function graph use ftrace directly")
The 'ftrace_common_return' label has been unused.
Remove it.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: "Ivan T. Ivanov" <iivanov@suse.de>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220614080944.1349146-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Sometimes it is necessary to use a PLT entry to call an ftrace
trampoline. This is handled by ftrace_make_call() and ftrace_make_nop(),
with each having *almost* identical logic, but this is not handled by
ftrace_modify_call() since its introduction in commit:
3b23e4991f ("arm64: implement ftrace with regs")
Due to this, if we ever were to call ftrace_modify_call() for a callsite
which requires a PLT entry for a trampoline, then either:
a) If the old addr requires a trampoline, ftrace_modify_call() will use
an out-of-range address to generate the 'old' branch instruction.
This will result in warnings from aarch64_insn_gen_branch_imm() and
ftrace_modify_code(), and no instructions will be modified. As
ftrace_modify_call() will return an error, this will result in
subsequent internal ftrace errors.
b) If the old addr does not require a trampoline, but the new addr does,
ftrace_modify_call() will use an out-of-range address to generate the
'new' branch instruction. This will result in warnings from
aarch64_insn_gen_branch_imm(), and ftrace_modify_code() will replace
the 'old' branch with a BRK. This will result in a kernel panic when
this BRK is later executed.
Practically speaking, case (a) is vastly more likely than case (b), and
typically this will result in internal ftrace errors that don't
necessarily affect the rest of the system. This can be demonstrated with
an out-of-tree test module which triggers ftrace_modify_call(), e.g.
| # insmod test_ftrace.ko
| test_ftrace: Function test_function raw=0xffffb3749399201c, callsite=0xffffb37493992024
| branch_imm_common: offset out of range
| branch_imm_common: offset out of range
| ------------[ ftrace bug ]------------
| ftrace failed to modify
| [<ffffb37493992024>] test_function+0x8/0x38 [test_ftrace]
| actual: 1d:00:00:94
| Updating ftrace call site to call a different ftrace function
| ftrace record flags: e0000002
| (2) R
| expected tramp: ffffb374ae42ed54
| ------------[ cut here ]------------
| WARNING: CPU: 0 PID: 165 at kernel/trace/ftrace.c:2085 ftrace_bug+0x280/0x2b0
| Modules linked in: test_ftrace(+)
| CPU: 0 PID: 165 Comm: insmod Not tainted 5.19.0-rc2-00002-g4d9ead8b45ce #13
| Hardware name: linux,dummy-virt (DT)
| pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : ftrace_bug+0x280/0x2b0
| lr : ftrace_bug+0x280/0x2b0
| sp : ffff80000839ba00
| x29: ffff80000839ba00 x28: 0000000000000000 x27: ffff80000839bcf0
| x26: ffffb37493994180 x25: ffffb374b0991c28 x24: ffffb374b0d70000
| x23: 00000000ffffffea x22: ffffb374afcc33b0 x21: ffffb374b08f9cc8
| x20: ffff572b8462c000 x19: ffffb374b08f9000 x18: ffffffffffffffff
| x17: 6c6c6163202c6331 x16: ffffb374ae5ad110 x15: ffffb374b0d51ee4
| x14: 0000000000000000 x13: 3435646532346561 x12: 3437336266666666
| x11: 203a706d61727420 x10: 6465746365707865 x9 : ffffb374ae5149e8
| x8 : 336266666666203a x7 : 706d617274206465 x6 : 00000000fffff167
| x5 : ffff572bffbc4a08 x4 : 00000000fffff167 x3 : 0000000000000000
| x2 : 0000000000000000 x1 : ffff572b84461e00 x0 : 0000000000000022
| Call trace:
| ftrace_bug+0x280/0x2b0
| ftrace_replace_code+0x98/0xa0
| ftrace_modify_all_code+0xe0/0x144
| arch_ftrace_update_code+0x14/0x20
| ftrace_startup+0xf8/0x1b0
| register_ftrace_function+0x38/0x90
| test_ftrace_init+0xd0/0x1000 [test_ftrace]
| do_one_initcall+0x50/0x2b0
| do_init_module+0x50/0x1f0
| load_module+0x17c8/0x1d64
| __do_sys_finit_module+0xa8/0x100
| __arm64_sys_finit_module+0x2c/0x3c
| invoke_syscall+0x50/0x120
| el0_svc_common.constprop.0+0xdc/0x100
| do_el0_svc+0x3c/0xd0
| el0_svc+0x34/0xb0
| el0t_64_sync_handler+0xbc/0x140
| el0t_64_sync+0x18c/0x190
| ---[ end trace 0000000000000000 ]---
We can solve this by consistently determining whether to use a PLT entry
for an address.
Note that since (the earlier) commit:
f1a54ae9af ("arm64: module/ftrace: intialize PLT at load time")
... we can consistently determine the PLT address that a given callsite
will use, and therefore ftrace_make_nop() does not need to skip
validation when a PLT is in use.
This patch factors the existing logic out of ftrace_make_call() and
ftrace_make_nop() into a common ftrace_find_callable_addr() helper
function, which is used by ftrace_make_call(), ftrace_make_nop(), and
ftrace_modify_call(). In ftrace_make_nop() the patching is consistently
validated by ftrace_modify_code() as we can always determine what the
old instruction should have been.
Fixes: 3b23e4991f ("arm64: implement ftrace with regs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Will Deacon <will@kernel.org>
Tested-by: "Ivan T. Ivanov" <iivanov@suse.de>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220614080944.1349146-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The branch range checks in ftrace_make_call() and ftrace_make_nop() are
incorrect, erroneously permitting a forwards branch of 128M and
erroneously rejecting a backwards branch of 128M.
This is because both functions calculate the offset backwards,
calculating the offset *from* the target *to* the branch, rather than
the other way around as the later comparisons expect.
If an out-of-range branch were erroeously permitted, this would later be
rejected by aarch64_insn_gen_branch_imm() as branch_imm_common() checks
the bounds correctly, resulting in warnings and the placement of a BRK
instruction. Note that this can only happen for a forwards branch of
exactly 128M, and so the caller would need to be exactly 128M bytes
below the relevant ftrace trampoline.
If an in-range branch were erroeously rejected, then:
* For modules when CONFIG_ARM64_MODULE_PLTS=y, this would result in the
use of a PLT entry, which is benign.
Note that this is the common case, as this is selected by
CONFIG_RANDOMIZE_BASE (and therefore RANDOMIZE_MODULE_REGION_FULL),
which distributions typically seelct. This is also selected by
CONFIG_ARM64_ERRATUM_843419.
* For modules when CONFIG_ARM64_MODULE_PLTS=n, this would result in
internal ftrace failures.
* For core kernel text, this would result in internal ftrace failues.
Note that for this to happen, the kernel text would need to be at
least 128M bytes in size, and typical configurations are smaller tha
this.
Fix this by calculating the offset *from* the branch *to* the target in
both functions.
Fixes: f8af0b364e ("arm64: ftrace: don't validate branch via PLT in ftrace_make_nop()")
Fixes: e71a4e1beb ("arm64: ftrace: add support for far branches to dynamic ftrace")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Will Deacon <will@kernel.org>
Tested-by: "Ivan T. Ivanov" <iivanov@suse.de>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220614080944.1349146-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This reverts commit 73e2d827a5.
The reverted patch was needed as a fix after commit f5bda35fba
("random: use static branch for crng_ready()"). However, this was
already fixed by 60e5b2886b ("random: do not use jump labels before
they are initialized") and hence no longer necessary to initialise jump
labels before setup_machine_fdt().
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* Properly reset the SVE/SME flags on vcpu load
* Fix a vgic-v2 regression regarding accessing the pending
state of a HW interrupt from userspace (and make the code
common with vgic-v3)
* Fix access to the idreg range for protected guests
* Ignore 'kvm-arm.mode=protected' when using VHE
* Return an error from kvm_arch_init_vm() on allocation failure
* A bunch of small cleanups (comments, annotations, indentation)
RISC-V:
* Typo fix in arch/riscv/kvm/vmid.c
* Remove broken reference pattern from MAINTAINERS entry
x86-64:
* Fix error in page tables with MKTME enabled
* Dirty page tracking performance test extended to running a nested
guest
* Disable APICv/AVIC in cases that it cannot implement correctly
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"While last week's pull request contained miscellaneous fixes for x86,
this one covers other architectures, selftests changes, and a bigger
series for APIC virtualization bugs that were discovered during 5.20
development. The idea is to base 5.20 development for KVM on top of
this tag.
ARM64:
- Properly reset the SVE/SME flags on vcpu load
- Fix a vgic-v2 regression regarding accessing the pending state of a
HW interrupt from userspace (and make the code common with vgic-v3)
- Fix access to the idreg range for protected guests
- Ignore 'kvm-arm.mode=protected' when using VHE
- Return an error from kvm_arch_init_vm() on allocation failure
- A bunch of small cleanups (comments, annotations, indentation)
RISC-V:
- Typo fix in arch/riscv/kvm/vmid.c
- Remove broken reference pattern from MAINTAINERS entry
x86-64:
- Fix error in page tables with MKTME enabled
- Dirty page tracking performance test extended to running a nested
guest
- Disable APICv/AVIC in cases that it cannot implement correctly"
[ This merge also fixes a misplaced end parenthesis bug introduced in
commit 3743c2f025 ("KVM: x86: inhibit APICv/AVIC on changes to APIC
ID or APIC base") pointed out by Sean Christopherson ]
Link: https://lore.kernel.org/all/20220610191813.371682-1-seanjc@google.com/
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (34 commits)
KVM: selftests: Restrict test region to 48-bit physical addresses when using nested
KVM: selftests: Add option to run dirty_log_perf_test vCPUs in L2
KVM: selftests: Clean up LIBKVM files in Makefile
KVM: selftests: Link selftests directly with lib object files
KVM: selftests: Drop unnecessary rule for STATIC_LIBS
KVM: selftests: Add a helper to check EPT/VPID capabilities
KVM: selftests: Move VMX_EPT_VPID_CAP_AD_BITS to vmx.h
KVM: selftests: Refactor nested_map() to specify target level
KVM: selftests: Drop stale function parameter comment for nested_map()
KVM: selftests: Add option to create 2M and 1G EPT mappings
KVM: selftests: Replace x86_page_size with PG_LEVEL_XX
KVM: x86: SVM: fix nested PAUSE filtering when L0 intercepts PAUSE
KVM: x86: SVM: drop preempt-safe wrappers for avic_vcpu_load/put
KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking
KVM: x86: disable preemption while updating apicv inhibition
KVM: x86: SVM: fix avic_kick_target_vcpus_fast
KVM: x86: SVM: remove avic's broken code that updated APIC ID
KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base
KVM: x86: document AVIC/APICv inhibit reasons
KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs
...
- SME save/restore for EFI fix - incorrect logic for detecting the need
for saving/restoring the FFR state.
- SME fix for a CPU ID field value.
- Sysreg generation awk script fix (comparison operator).
- Some typos in documentation or comments and silence a sparse warning
(missing prototype).
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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- SME save/restore for EFI fix - incorrect logic for detecting the need
for saving/restoring the FFR state.
- SME fix for a CPU ID field value.
- Sysreg generation awk script fix (comparison operator).
- Some typos in documentation or comments and silence a sparse warning
(missing prototype).
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Add kasan_hw_tags_enable() prototype to silence sparse
arm64/sme: Fix EFI save/restore
arm64/fpsimd: Fix typo in comment
arm64/sysreg: Fix typo in Enum element regex
arm64/sme: Fix SVE/SME typo in ABI documentation
arm64/sme: Fix tests for 0b1111 value ID registers
This function is only called from assembly, no need for a prototype
declaration in a header file. In addition, add #ifdef around the
function since it is only used when CONFIG_KASAN_HW_TAGS.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
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Merge tag 'for-linus-5.19a-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- a small cleanup removing "export" of an __init function
- a small series adding a new infrastructure for platform flags
- a series adding generic virtio support for Xen guests (frontend side)
* tag 'for-linus-5.19a-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: unexport __init-annotated xen_xlate_map_ballooned_pages()
arm/xen: Assign xen-grant DMA ops for xen-grant DMA devices
xen/grant-dma-ops: Retrieve the ID of backend's domain for DT devices
xen/grant-dma-iommu: Introduce stub IOMMU driver
dt-bindings: Add xen,grant-dma IOMMU description for xen-grant DMA ops
xen/virtio: Enable restricted memory access using Xen grant mappings
xen/grant-dma-ops: Add option to restrict memory access under Xen
xen/grants: support allocating consecutive grants
arm/xen: Introduce xen_setup_dma_ops()
virtio: replace arch_has_restricted_virtio_memory_access()
kernel: add platform_has() infrastructure
The EFI save/restore code is confused. When saving the check for saving
FFR is inverted due to confusion with the streaming mode check, and when
restoring we check if we need to restore FFR by checking the percpu
efi_sm_state without the required wrapper rather than based on the
combination of FA64 support and streaming mode.
Fixes: e0838f6373 ("arm64/sme: Save and restore streaming mode over EFI runtime calls")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220602124132.3528951-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In the awk script, there was a typo with the comparison operator when
checking if the matched pattern is inside an Enum block.
This prevented the generation of the whole sysreg-defs.h header.
Fixes: 66847e0618 ("arm64: Add sysreg header generation scripting")
Signed-off-by: Alejandro Tafalla <atafalla@dnyon.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220609204220.12112-1-atafalla@dnyon.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The layout of 'struct kvm_vcpu_arch' has evolved significantly since
the initial port of KVM/arm64, so remove the stale comment suggesting
that a prefix of the structure is used exclusively from assembly code.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-7-will@kernel.org
host_stage2_try() asserts that the KVM host lock is held, so there's no
need to duplicate the assertion in its wrappers.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-6-will@kernel.org
has_vhe() expands to a compile-time constant when evaluated from the VHE
or nVHE code, alternatively checking a static key when called from
elsewhere in the kernel. On face value, this looks like a case of
premature optimization, but in fact this allows symbol references on
VHE-specific code paths to be dropped from the nVHE object.
Expand the comment in has_vhe() to make this clearer, hopefully
discouraging anybody from simplifying the code.
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-5-will@kernel.org
Ignore 'kvm-arm.mode=protected' when using VHE so that kvm_get_mode()
only returns KVM_MODE_PROTECTED on systems where the feature is available.
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-4-will@kernel.org
A protected VM accessing ID_AA64ISAR2_EL1 gets punished with an UNDEF,
while it really should only get a zero back if the register is not
handled by the hypervisor emulation (as mandated by the architecture).
Introduce all the missing ID registers (including the unallocated ones),
and have them to return 0.
Reported-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-3-will@kernel.org
If we fail to allocate the 'supported_cpus' cpumask in kvm_arch_init_vm()
then be sure to return -ENOMEM instead of success (0) on the failure
path.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-2-will@kernel.org
For both ID_AA64SMFR0_EL1.I16I64 and ID_AA64SMFR0_EL1.I8I32 we check for
the presence of the feature by looking for a specific ID value of 0x4 but
should instead be checking for the value 0xf defined by the architecture.
This had no practical effect since we are looking for values >= our define
and the only valid values in the architecture are 0b0000 and 0b1111 so we
would detect things appropriately with the architecture as it stands even
with the incorrect defines.
Signed-off-by: Mark Brown <broonie@kernel.org>
Fixes: b4adc83b07 ("arm64/sme: System register and exception syndrome definitions")
Link: https://lore.kernel.org/r/20220607165128.2833157-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
A recurrent bug in the KVM/arm64 code base consists in trying to
access the timer pending state outside of the vcpu context, which
makes zero sense (the pending state only exists when the vcpu
is loaded).
In order to avoid more embarassing crashes and catch the offenders
red-handed, add a warning to kvm_arch_timer_get_input_level() and
return the state as non-pending. This avoids taking the system down,
and still helps tracking down silly bugs.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220607131427.1164881-4-maz@kernel.org
Now that GICv2 has a proper userspace accessor for the pending state,
switch GICv3 over to it, dropping the local version, moving over the
specific behaviours that CGIv3 requires (such as the distinction
between pending latch and line level which were never enforced
with GICv2).
We also gain extra locking that isn't really necessary for userspace,
but that's a small price to pay for getting rid of superfluous code.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20220607131427.1164881-3-maz@kernel.org
syzbot reported an illegal copy_to_user() attempt
from bpf_prog_get_info_by_fd() [1]
There was no repro yet on this bug, but I think
that commit 0aef499f31 ("mm/usercopy: Detect vmalloc overruns")
is exposing a prior bug in bpf arm64.
bpf_prog_get_info_by_fd() looks at prog->jited_len
to determine if the JIT image can be copied out to user space.
My theory is that syzbot managed to get a prog where prog->jited_len
has been set to 43, while prog->bpf_func has ben cleared.
It is not clear why copy_to_user(uinsns, NULL, ulen) is triggering
this particular warning.
I thought find_vma_area(NULL) would not find a vm_struct.
As we do not hold vmap_area_lock spinlock, it might be possible
that the found vm_struct was garbage.
[1]
usercopy: Kernel memory exposure attempt detected from vmalloc (offset 792633534417210172, size 43)!
kernel BUG at mm/usercopy.c:101!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 25002 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-10139-g8291eaafed36 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : usercopy_abort+0x90/0x94 mm/usercopy.c:101
lr : usercopy_abort+0x90/0x94 mm/usercopy.c:89
sp : ffff80000b773a20
x29: ffff80000b773a30 x28: faff80000b745000 x27: ffff80000b773b48
x26: 0000000000000000 x25: 000000000000002b x24: 0000000000000000
x23: 00000000000000e0 x22: ffff80000b75db67 x21: 0000000000000001
x20: 000000000000002b x19: ffff80000b75db3c x18: 00000000fffffffd
x17: 2820636f6c6c616d x16: 76206d6f72662064 x15: 6574636574656420
x14: 74706d6574746120 x13: 2129333420657a69 x12: 73202c3237313031
x11: 3237313434333533 x10: 3336323937207465 x9 : 657275736f707865
x8 : ffff80000a30c550 x7 : ffff80000b773830 x6 : ffff80000b773830
x5 : 0000000000000000 x4 : ffff00007fbbaa10 x3 : 0000000000000000
x2 : 0000000000000000 x1 : f7ff000028fc0000 x0 : 0000000000000064
Call trace:
usercopy_abort+0x90/0x94 mm/usercopy.c:89
check_heap_object mm/usercopy.c:186 [inline]
__check_object_size mm/usercopy.c:252 [inline]
__check_object_size+0x198/0x36c mm/usercopy.c:214
check_object_size include/linux/thread_info.h:199 [inline]
check_copy_size include/linux/thread_info.h:235 [inline]
copy_to_user include/linux/uaccess.h:159 [inline]
bpf_prog_get_info_by_fd.isra.0+0xf14/0xfdc kernel/bpf/syscall.c:3993
bpf_obj_get_info_by_fd+0x12c/0x510 kernel/bpf/syscall.c:4253
__sys_bpf+0x900/0x2150 kernel/bpf/syscall.c:4956
__do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
__arm64_sys_bpf+0x28/0x40 kernel/bpf/syscall.c:5019
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52
el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142
do_el0_svc+0xa0/0xc0 arch/arm64/kernel/syscall.c:206
el0_svc+0x44/0xb0 arch/arm64/kernel/entry-common.c:624
el0t_64_sync_handler+0x1ac/0x1b0 arch/arm64/kernel/entry-common.c:642
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581
Code: aa0003e3 d00038c0 91248000 97fff65f (d4210000)
Fixes: db496944fd ("bpf: arm64: add JIT support for multi-function programs")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220531215113.1100754-1-eric.dumazet@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since 5bfa685e62 ("KVM: arm64: vgic: Read HW interrupt pending state
from the HW"), we're able to source the pending bit for an interrupt
that is stored either on the physical distributor or on a device.
However, this state is only available when the vcpu is loaded,
and is not intended to be accessed from userspace. Unfortunately,
the GICv2 emulation doesn't provide specific userspace accessors,
and we fallback with the ones that are intended for the guest,
with fatal consequences.
Add a new vgic_uaccess_read_pending() accessor for userspace
to use, build on top of the existing vgic_mmio_read_pending().
Reported-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Fixes: 5bfa685e62 ("KVM: arm64: vgic: Read HW interrupt pending state from the HW")
Link: https://lore.kernel.org/r/20220607131427.1164881-2-maz@kernel.org
Cc: stable@vger.kernel.org
On each vcpu load, we set the KVM_ARM64_HOST_SME_ENABLED
flag if SME is enabled for EL0 on the host. This is used to
restore the correct state on vpcu put.
However, it appears that nothing ever clears this flag. Once
set, it will stick until the vcpu is destroyed, which has the
potential to spuriously enable SME for userspace. As it turns
out, this is due to the SME code being more or less copied from
SVE, and inheriting the same shortcomings.
We never saw the issue because nothing uses SME, and the amount
of testing is probably still pretty low.
Fixes: 861262ab86 ("KVM: arm64: Handle SME host state when running guests")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220528113829.1043361-3-maz@kernel.org
On each vcpu load, we set the KVM_ARM64_HOST_SVE_ENABLED
flag if SVE is enabled for EL0 on the host. This is used to restore
the correct state on vpcu put.
However, it appears that nothing ever clears this flag. Once
set, it will stick until the vcpu is destroyed, which has the
potential to spuriously enable SVE for userspace.
We probably never saw the issue because no VMM uses SVE, but
that's still pretty bad. Unconditionally clearing the flag
on vcpu load addresses the issue.
Fixes: 8383741ab2 ("KVM: arm64: Get rid of host SVE tracking/saving")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220528113829.1043361-2-maz@kernel.org
This patch introduces new helper and places it in new header.
The helper's purpose is to assign any Xen specific DMA ops in
a single place. For now, we deal with xen-swiotlb DMA ops only.
The one of the subsequent commits in current series will add
xen-grant DMA ops case.
Also re-use the xen_swiotlb_detect() check on Arm32.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
[For arm64]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1654197833-25362-2-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
ordinary user mode tasks.
In commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
The commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple enough
to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code sitting
in linux-next.
Link: https://lkml.kernel.org/r/87mtfu4up3.fsf@email.froward.int.ebiederm.org
Eric W. Biederman (8):
kthread: Don't allocate kthread_struct for init and umh
fork: Pass struct kernel_clone_args into copy_thread
fork: Explicity test for idle tasks in copy_thread
fork: Generalize PF_IO_WORKER handling
init: Deal with the init process being a user mode process
fork: Explicitly set PF_KTHREAD
fork: Stop allowing kthreads to call execve
sched: Update task_tick_numa to ignore tasks without an mm
arch/alpha/kernel/process.c | 13 ++++++------
arch/arc/kernel/process.c | 13 ++++++------
arch/arm/kernel/process.c | 12 ++++++-----
arch/arm64/kernel/process.c | 12 ++++++-----
arch/csky/kernel/process.c | 15 ++++++-------
arch/h8300/kernel/process.c | 10 ++++-----
arch/hexagon/kernel/process.c | 12 ++++++-----
arch/ia64/kernel/process.c | 15 +++++++------
arch/m68k/kernel/process.c | 12 ++++++-----
arch/microblaze/kernel/process.c | 12 ++++++-----
arch/mips/kernel/process.c | 13 ++++++------
arch/nios2/kernel/process.c | 12 ++++++-----
arch/openrisc/kernel/process.c | 12 ++++++-----
arch/parisc/kernel/process.c | 18 +++++++++-------
arch/powerpc/kernel/process.c | 15 +++++++------
arch/riscv/kernel/process.c | 12 ++++++-----
arch/s390/kernel/process.c | 12 ++++++-----
arch/sh/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_32.c | 12 ++++++-----
arch/sparc/kernel/process_64.c | 12 ++++++-----
arch/um/kernel/process.c | 15 +++++++------
arch/x86/include/asm/fpu/sched.h | 2 +-
arch/x86/include/asm/switch_to.h | 8 +++----
arch/x86/kernel/fpu/core.c | 4 ++--
arch/x86/kernel/process.c | 18 +++++++++-------
arch/xtensa/kernel/process.c | 17 ++++++++-------
fs/exec.c | 8 ++++---
include/linux/sched/task.h | 8 +++++--
init/initramfs.c | 2 ++
init/main.c | 2 +-
kernel/fork.c | 46 +++++++++++++++++++++++++++++++++-------
kernel/sched/fair.c | 2 +-
kernel/umh.c | 6 +++---
33 files changed, 234 insertions(+), 160 deletions(-)
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Merge tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
