| Message ID | 20220224051439.640768-7-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Hypervisor stack enhancements | expand |
Hi Kalesh, On Thu, Feb 24, 2022 at 5:21 AM 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> > --- > arch/arm64/kvm/hyp/nvhe/host.S | 5 +++++ > arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ > 2 files changed, 10 insertions(+) > > diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S > index 749961bfa5ba..367a01e8abed 100644 > --- a/arch/arm64/kvm/hyp/nvhe/host.S > +++ b/arch/arm64/kvm/hyp/nvhe/host.S > @@ -179,6 +179,10 @@ 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 > @@ -186,6 +190,7 @@ SYM_FUNC_END(__host_hvc) > */ Nit: Maybe you should update this comment as well, since whether it corrupts the stack or not depends on what happens above with CONFIG_NVHE_EL2_DEBUG. Thanks, /fuad > 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; > -- > 2.35.1.473.g83b2b277ed-goog >
On Thu, Feb 24, 2022 at 4:27 AM Fuad Tabba <tabba@google.com> wrote: > > Hi Kalesh, > > On Thu, Feb 24, 2022 at 5:21 AM 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> > > --- > > arch/arm64/kvm/hyp/nvhe/host.S | 5 +++++ > > arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ > > 2 files changed, 10 insertions(+) > > > > diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S > > index 749961bfa5ba..367a01e8abed 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/host.S > > +++ b/arch/arm64/kvm/hyp/nvhe/host.S > > @@ -179,6 +179,10 @@ 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 > > @@ -186,6 +190,7 @@ SYM_FUNC_END(__host_hvc) > > */ > > Nit: Maybe you should update this comment as well, since whether it > corrupts the stack or not depends on what happens above with > CONFIG_NVHE_EL2_DEBUG. Ack, will update it in the next version. Thanks, Kalesh > > Thanks, > /fuad > > > 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; > > -- > > 2.35.1.473.g83b2b277ed-goog > >
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 749961bfa5ba..367a01e8abed 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -179,6 +179,10 @@ 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 @@ -186,6 +190,7 @@ SYM_FUNC_END(__host_hvc) */ 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> --- arch/arm64/kvm/hyp/nvhe/host.S | 5 +++++ arch/arm64/kvm/hyp/nvhe/switch.c | 5 +++++ 2 files changed, 10 insertions(+)