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ANDROID: KVM: arm64: Add PKVM_DISABLE_STAGE2_ON_PANIC

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Now pKVM prefaults the entire host stage-2, it is very unlikely to
encounter a fault on the panic path and the need for disabling the host
stage-2 on panic for debug purpose isn't that obvious anymore. Let's
make it a separate config option. This will allow to enable other debug
options which do not jeopardize the system security.

Bug: 357781595
Change-Id: I945e95c0e5073f51e3c4716532eaf19999146187
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
This commit is contained in:
Vincent Donnefort
2025-02-21 14:34:11 +00:00
parent e19e2557a0
commit b526a11319
2 changed files with 14 additions and 1 deletions
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13
arch/arm64/kvm/Kconfig
View File

@@ -92,6 +92,19 @@ config PROTECTED_NVHE_STACKTRACE
If unsure, or not using protected nVHE (pKVM), say N.
config PKVM_DISABLE_STAGE2_ON_PANIC
bool "Disable the host stage-2 on panic"
default n
depends on NVHE_EL2_DEBUG
help
If panic occurs while the host lock is held and if, plagued by bad
luck the panic path triggers a host stage-2 memory abort, a lockup
would happen. The only way out is to disable the stage-2 page-table.
This however tamper the system security. This option should therefore
solely be enabled to debug specific issues.
Just say N.
config PTDUMP_STAGE2_DEBUGFS
bool "Present the stage-2 pagetables to debugfs"
depends on KVM

2
arch/arm64/kvm/hyp/nvhe/host.S
View File

@@ -120,7 +120,7 @@ SYM_FUNC_START(__hyp_do_panic)
mov x29, x0
#ifdef CONFIG_NVHE_EL2_DEBUG
#ifdef CONFIG_PKVM_DISABLE_STAGE2_ON_PANIC
/* Ensure host stage-2 is disabled */
mrs x0, hcr_el2
bic x0, x0, #HCR_VM