| Message ID | 20220314200148.2695206-7-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Hypervisor stack enhancements | expand |
Hi Kalesh, On Mon, Mar 14, 2022 at 8:05 PM Kalesh Singh <kaleshsingh@google.com> wrote: > > Allocate and switch to 16-byte aligned secondary stack on overflow. This > provides us stack space to better handle overflows; and is used in > a subsequent patch to dump the hypervisor stacktrace. The overflow stack > is only allocated if CONFIG_NVHE_EL2_DEBUG is enabled, as hypervisor > stacktraces is a debug feature dependent on CONFIG_NVHE_EL2_DEBUG. > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Tested-by: Fuad Tabba <tabba@google.com> Reviewed-by: Fuad Tabba <tabba@google.com> Thanks, /fuad > --- > > Changes in v4: > - Update comment to clarify resetting the SP to the top of the stack > only happens if CONFIG_NVHE_EL2_DEBUG is disabled, per Fuad > > > arch/arm64/kvm/hyp/nvhe/host.S | 11 ++++++++--- > arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ > 2 files changed, 13 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S > index be6d844279b1..a0c4b4f1549f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/host.S > +++ b/arch/arm64/kvm/hyp/nvhe/host.S > @@ -179,13 +179,18 @@ SYM_FUNC_END(__host_hvc) > b hyp_panic > > .L__hyp_sp_overflow\@: > +#ifdef CONFIG_NVHE_EL2_DEBUG > + /* Switch to the overflow stack */ > + adr_this_cpu sp, hyp_overflow_stack + PAGE_SIZE, x0 > +#else > /* > - * Reset SP to the top of the stack, to allow handling the hyp_panic. > - * This corrupts the stack but is ok, since we won't be attempting > - * any unwinding here. > + * If !CONFIG_NVHE_EL2_DEBUG, reset SP to the top of the stack, to > + * allow handling the hyp_panic. This corrupts the stack but is ok, > + * since we won't be attempting any unwinding here. > */ > ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 > mov sp, x0 > +#endif > > bl hyp_panic_bad_stack > ASM_BUG() > diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c > index 703a5d3f611b..efc20273a352 100644 > --- a/arch/arm64/kvm/hyp/nvhe/switch.c > +++ b/arch/arm64/kvm/hyp/nvhe/switch.c > @@ -34,6 +34,11 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data); > DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); > DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); > > +#ifdef CONFIG_NVHE_EL2_DEBUG > +DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack) > + __aligned(16); > +#endif > + > static void __activate_traps(struct kvm_vcpu *vcpu) > { > u64 val; > -- > 2.35.1.723.g4982287a31-goog >
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index be6d844279b1..a0c4b4f1549f 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -179,13 +179,18 @@ SYM_FUNC_END(__host_hvc) b hyp_panic .L__hyp_sp_overflow\@: +#ifdef CONFIG_NVHE_EL2_DEBUG + /* Switch to the overflow stack */ + adr_this_cpu sp, hyp_overflow_stack + PAGE_SIZE, x0 +#else /* - * Reset SP to the top of the stack, to allow handling the hyp_panic. - * This corrupts the stack but is ok, since we won't be attempting - * any unwinding here. + * If !CONFIG_NVHE_EL2_DEBUG, reset SP to the top of the stack, to + * allow handling the hyp_panic. This corrupts the stack but is ok, + * since we won't be attempting any unwinding here. */ ldr_this_cpu x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1 mov sp, x0 +#endif bl hyp_panic_bad_stack ASM_BUG() diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 703a5d3f611b..efc20273a352 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -34,6 +34,11 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data); DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); +#ifdef CONFIG_NVHE_EL2_DEBUG +DEFINE_PER_CPU(unsigned long [PAGE_SIZE/sizeof(long)], hyp_overflow_stack) + __aligned(16); +#endif + static void __activate_traps(struct kvm_vcpu *vcpu) { u64 val;
Allocate and switch to 16-byte aligned secondary stack on overflow. This provides us stack space to better handle overflows; and is used in a subsequent patch to dump the hypervisor stacktrace. The overflow stack is only allocated if CONFIG_NVHE_EL2_DEBUG is enabled, as hypervisor stacktraces is a debug feature dependent on CONFIG_NVHE_EL2_DEBUG. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v4: - Update comment to clarify resetting the SP to the top of the stack only happens if CONFIG_NVHE_EL2_DEBUG is disabled, per Fuad arch/arm64/kvm/hyp/nvhe/host.S | 11 ++++++++--- arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ 2 files changed, 13 insertions(+), 3 deletions(-)