| Message ID | 20220721055728.718573-10-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM nVHE Hypervisor stack unwinder | expand |
Hi Kalesh, On Thu, Jul 21, 2022 at 6:57 AM Kalesh Singh <kaleshsingh@google.com> wrote: > > 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 seried to dump the nit: seried/series > nVHE hypervisor stacktrace when using protected-mode. > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> > --- Reviewed-by: Fuad Tabba <tabba@google.com> Cheers, /fuad > Changes in v5: > - Fix typo in commit text, per Marc > > arch/arm64/include/asm/memory.h | 8 ++++++++ > arch/arm64/kvm/hyp/nvhe/stacktrace.c | 4 ++++ > 2 files changed, 12 insertions(+) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 0af70d9abede..cab80a9a4086 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -113,6 +113,14 @@ > > #define OVERFLOW_STACK_SIZE SZ_4K > > +/* > + * With the minimum frame size of [x29, x30], exactly half the combined > + * sizes of the hyp and overflow stacks is the maximum size needed to > + * save the unwinded stacktrace; plus an additional entry to delimit the > + * end. > + */ > +#define NVHE_STACKTRACE_SIZE ((OVERFLOW_STACK_SIZE + PAGE_SIZE) / 2 + sizeof(long)) > + > /* > * Alignment of kernel segments (e.g. .text, .data). > * > diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c > index a3d5b34e1249..69e65b457f1c 100644 > --- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c > +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c > @@ -9,3 +9,7 @@ > > DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) > __aligned(16); > + > +#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE > +DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace); > +#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */ > -- > 2.37.0.170.g444d1eabd0-goog >
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 0af70d9abede..cab80a9a4086 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -113,6 +113,14 @@ #define OVERFLOW_STACK_SIZE SZ_4K +/* + * With the minimum frame size of [x29, x30], exactly half the combined + * sizes of the hyp and overflow stacks is the maximum size needed to + * save the unwinded stacktrace; plus an additional entry to delimit the + * end. + */ +#define NVHE_STACKTRACE_SIZE ((OVERFLOW_STACK_SIZE + PAGE_SIZE) / 2 + sizeof(long)) + /* * Alignment of kernel segments (e.g. .text, .data). * diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c index a3d5b34e1249..69e65b457f1c 100644 --- a/arch/arm64/kvm/hyp/nvhe/stacktrace.c +++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c @@ -9,3 +9,7 @@ DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) __aligned(16); + +#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE +DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace); +#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
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 seried to dump the nVHE hypervisor stacktrace when using protected-mode. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v5: - Fix typo in commit text, per Marc arch/arm64/include/asm/memory.h | 8 ++++++++ arch/arm64/kvm/hyp/nvhe/stacktrace.c | 4 ++++ 2 files changed, 12 insertions(+)