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Make the dependency with EL2_DEBUG more obvious by moving the
stacktrace configurtion *after* it.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20220727142906.1856759-2-maz@kernel.org
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Dumps the pKVM hypervisor backtrace from EL1 by reading the unwinded
addresses from the shared stacktrace buffer.
The nVHE hyp backtrace is dumped on hyp_panic(), before panicking the
host.
[ 111.623091] kvm [367]: nVHE call trace:
[ 111.623215] kvm [367]: [<ffff8000090a6570>] __kvm_nvhe_hyp_panic+0xac/0xf8
[ 111.623448] kvm [367]: [<ffff8000090a65cc>] __kvm_nvhe_hyp_panic_bad_stack+0x10/0x10
[ 111.623642] kvm [367]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
. . .
[ 111.640366] kvm [367]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[ 111.640467] kvm [367]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[ 111.640574] kvm [367]: [<ffff8000090a5de4>] __kvm_nvhe___kvm_vcpu_run+0x30/0x40c
[ 111.640676] kvm [367]: [<ffff8000090a8b64>] __kvm_nvhe_handle___kvm_vcpu_run+0x30/0x48
[ 111.640778] kvm [367]: [<ffff8000090a88b8>] __kvm_nvhe_handle_trap+0xc4/0x128
[ 111.640880] kvm [367]: [<ffff8000090a7864>] __kvm_nvhe___host_exit+0x64/0x64
[ 111.640996] kvm [367]: ---[ end nVHE call trace ]---
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-18-kaleshsingh@google.com
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Implements the common framework necessary for unwind() to work in
the protected nVHE context:
- on_accessible_stack()
- on_overflow_stack()
- unwind_next()
Protected nVHE unwind() is used to unwind and save the hyp stack
addresses to the shared stacktrace buffer. The host reads the
entries in this buffer, symbolizes and dumps the stacktrace (later
patch 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/20220726073750.3219117-17-kaleshsingh@google.com
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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
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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
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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
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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
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In non-protected nVHE mode, unwinds and dumps the hypervisor backtrace
from EL1. This is possible beacause the host can directly access the
hypervisor stack pages in non-protected mode.
The nVHE backtrace is dumped on hyp_panic(), before panicking the host.
[ 101.498183] kvm [377]: nVHE call trace:
[ 101.498363] kvm [377]: [<ffff8000090a6570>] __kvm_nvhe_hyp_panic+0xac/0xf8
[ 101.499045] kvm [377]: [<ffff8000090a65cc>] __kvm_nvhe_hyp_panic_bad_stack+0x10/0x10
[ 101.499498] kvm [377]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
. . .
[ 101.524929] kvm [377]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[ 101.525062] kvm [377]: [<ffff8000090a61e4>] __kvm_nvhe_recursive_death+0x24/0x34
[ 101.525195] kvm [377]: [<ffff8000090a5de4>] __kvm_nvhe___kvm_vcpu_run+0x30/0x40c
[ 101.525333] kvm [377]: [<ffff8000090a8b64>] __kvm_nvhe_handle___kvm_vcpu_run+0x30/0x48
[ 101.525468] kvm [377]: [<ffff8000090a88b8>] __kvm_nvhe_handle_trap+0xc4/0x128
[ 101.525602] kvm [377]: [<ffff8000090a7864>] __kvm_nvhe___host_exit+0x64/0x64
[ 101.525745] kvm [377]: ---[ end nVHE call trace ]---
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-12-kaleshsingh@google.com
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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
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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
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