| Message ID | 20220225033548.1912117-5-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Hypervisor stack enhancements | expand |
On Fri, 25 Feb 2022 03:34:49 +0000, Kalesh Singh <kaleshsingh@google.com> wrote: > > Maps the stack pages in the flexible private VA range and allocates > guard pages below the stack as unbacked VA space. The stack is aligned > to twice its size to aid overflow detection (implemented in a subsequent > patch in the series). > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> > --- > > Changes in v4: > - Replace IS_ERR_OR_NULL check with IS_ERR check now that > pkvm_alloc_private_va_range() returns an error for null > pointer, per Fuad > > Changes in v3: > - Handle null ptr in IS_ERR_OR_NULL checks, per Mark > > arch/arm64/kvm/hyp/nvhe/setup.c | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c > index 27af337f9fea..1b69a25c1861 100644 > --- a/arch/arm64/kvm/hyp/nvhe/setup.c > +++ b/arch/arm64/kvm/hyp/nvhe/setup.c > @@ -105,11 +105,28 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, > if (ret) > return ret; > > - end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; > + /* > + * Private mappings are allocated upwards from __io_map_base > + * so allocate the guard page first then the stack. > + */ > + start = (void *)pkvm_alloc_private_va_range(PAGE_SIZE, PAGE_SIZE); > + if (IS_ERR(start)) > + return PTR_ERR(start); > + > + /* > + * The stack is aligned to twice its size to facilitate overflow > + * detection. > + */ > + end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_pa; > start = end - PAGE_SIZE; > - ret = pkvm_create_mappings(start, end, PAGE_HYP); > - if (ret) > - return ret; > + start = (void *)__pkvm_create_private_mapping((phys_addr_t)start, > + PAGE_SIZE, PAGE_SIZE * 2, PAGE_HYP); Similar comments as the previous patch. I'd rather you treat each stack as a two-page VA, populated by a single page. It would be a lot clearer, and less fragile. > + if (IS_ERR(start)) > + return PTR_ERR(start); > + end = start + PAGE_SIZE; > + > + /* Update stack_hyp_va to end of the stack's private VA range */ > + per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va = (unsigned long) end; > } > > /* Thanks, M.
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 27af337f9fea..1b69a25c1861 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -105,11 +105,28 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, if (ret) return ret; - end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; + /* + * Private mappings are allocated upwards from __io_map_base + * so allocate the guard page first then the stack. + */ + start = (void *)pkvm_alloc_private_va_range(PAGE_SIZE, PAGE_SIZE); + if (IS_ERR(start)) + return PTR_ERR(start); + + /* + * The stack is aligned to twice its size to facilitate overflow + * detection. + */ + end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_pa; start = end - PAGE_SIZE; - ret = pkvm_create_mappings(start, end, PAGE_HYP); - if (ret) - return ret; + start = (void *)__pkvm_create_private_mapping((phys_addr_t)start, + PAGE_SIZE, PAGE_SIZE * 2, PAGE_HYP); + if (IS_ERR(start)) + return PTR_ERR(start); + end = start + PAGE_SIZE; + + /* Update stack_hyp_va to end of the stack's private VA range */ + per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va = (unsigned long) end; } /*
Maps the stack pages in the flexible private VA range and allocates guard pages below the stack as unbacked VA space. The stack is aligned to twice its size to aid overflow detection (implemented in a subsequent patch in the series). Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v4: - Replace IS_ERR_OR_NULL check with IS_ERR check now that pkvm_alloc_private_va_range() returns an error for null pointer, per Fuad Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/kvm/hyp/nvhe/setup.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)