| Message ID | 20220314200148.2695206-5-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 8:04 PM Kalesh Singh <kaleshsingh@google.com> wrote: > > Map the stack pages in the flexible private VA range and allocate > guard pages below the stack as unbacked VA space. The stack is aligned > so that any valid stack address has PAGE_SHIFT bit as 1 - this is used > for overflow detection (implemented in a subsequent patch in the series) > > 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 v6: > - Update call to pkvm_alloc_private_va_range() (return val and params) > > Changes in v5: > - Use a single allocation for stack and guard pages to ensure they > are contiguous, per Marc > > 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 | 31 ++++++++++++++++++++++++++++--- > 1 file changed, 28 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c > index 27af337f9fea..e8d4ea2fcfa0 100644 > --- a/arch/arm64/kvm/hyp/nvhe/setup.c > +++ b/arch/arm64/kvm/hyp/nvhe/setup.c > @@ -99,17 +99,42 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, > return ret; > > for (i = 0; i < hyp_nr_cpus; i++) { > + struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i); > + unsigned long hyp_addr; > + > start = (void *)kern_hyp_va(per_cpu_base[i]); > end = start + PAGE_ALIGN(hyp_percpu_size); > ret = pkvm_create_mappings(start, end, PAGE_HYP); > if (ret) > return ret; > > - end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; > - start = end - PAGE_SIZE; > - ret = pkvm_create_mappings(start, end, PAGE_HYP); > + /* > + * Allocate a contiguous HYP private VA range for the stack > + * and guard page. The allocation is also aligned based on > + * the order of its size. > + */ > + ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr); > + if (ret) > + return ret; > + > + /* > + * Since the stack grows downwards, map the stack to the page > + * at the higher address and leave the lower guard page > + * unbacked. > + * > + * Any valid stack address now has the PAGE_SHIFT bit as 1 > + * and addresses corresponding to the guard page have the > + * PAGE_SHIFT bit as 0 - this is used for overflow detection. > + */ > + hyp_spin_lock(&pkvm_pgd_lock); > + ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE, > + PAGE_SIZE, params->stack_pa, PAGE_HYP); > + hyp_spin_unlock(&pkvm_pgd_lock); > if (ret) > return ret; > + > + /* Update stack_hyp_va to end of the stack's private VA range */ > + params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE); > } > > /* > -- > 2.35.1.723.g4982287a31-goog >
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 27af337f9fea..e8d4ea2fcfa0 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -99,17 +99,42 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, return ret; for (i = 0; i < hyp_nr_cpus; i++) { + struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i); + unsigned long hyp_addr; + start = (void *)kern_hyp_va(per_cpu_base[i]); end = start + PAGE_ALIGN(hyp_percpu_size); ret = pkvm_create_mappings(start, end, PAGE_HYP); if (ret) return ret; - end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; - start = end - PAGE_SIZE; - ret = pkvm_create_mappings(start, end, PAGE_HYP); + /* + * Allocate a contiguous HYP private VA range for the stack + * and guard page. The allocation is also aligned based on + * the order of its size. + */ + ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr); + if (ret) + return ret; + + /* + * Since the stack grows downwards, map the stack to the page + * at the higher address and leave the lower guard page + * unbacked. + * + * Any valid stack address now has the PAGE_SHIFT bit as 1 + * and addresses corresponding to the guard page have the + * PAGE_SHIFT bit as 0 - this is used for overflow detection. + */ + hyp_spin_lock(&pkvm_pgd_lock); + ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE, + PAGE_SIZE, params->stack_pa, PAGE_HYP); + hyp_spin_unlock(&pkvm_pgd_lock); if (ret) return ret; + + /* Update stack_hyp_va to end of the stack's private VA range */ + params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE); } /*
Map the stack pages in the flexible private VA range and allocate guard pages below the stack as unbacked VA space. The stack is aligned so that any valid stack address has PAGE_SHIFT bit as 1 - this is used for overflow detection (implemented in a subsequent patch in the series) Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v6: - Update call to pkvm_alloc_private_va_range() (return val and params) Changes in v5: - Use a single allocation for stack and guard pages to ensure they are contiguous, per Marc 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 | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)