@@ -169,6 +169,7 @@ struct kvm_nvhe_init_params {
unsigned long tcr_el2;
unsigned long tpidr_el2;
unsigned long stack_hyp_va;
+ unsigned long stack_pa;
phys_addr_t pgd_pa;
unsigned long hcr_el2;
unsigned long vttbr;
@@ -1541,7 +1541,6 @@ static void cpu_prepare_hyp_mode(int cpu)
tcr |= (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET;
params->tcr_el2 = tcr;
- params->stack_hyp_va = kern_hyp_va(per_cpu(kvm_arm_hyp_stack_page, cpu) + PAGE_SIZE);
params->pgd_pa = kvm_mmu_get_httbr();
if (is_protected_kvm_enabled())
params->hcr_el2 = HCR_HOST_NVHE_PROTECTED_FLAGS;
@@ -1990,14 +1989,41 @@ static int init_hyp_mode(void)
* Map the Hyp stack pages
*/
for_each_possible_cpu(cpu) {
+ struct kvm_nvhe_init_params *params = per_cpu_ptr_nvhe_sym(kvm_init_params, cpu);
char *stack_page = (char *)per_cpu(kvm_arm_hyp_stack_page, cpu);
- err = create_hyp_mappings(stack_page, stack_page + PAGE_SIZE,
- PAGE_HYP);
+ unsigned long stack_hyp_va, guard_hyp_va;
+ /*
+ * Private mappings are allocated downwards from io_map_base
+ * so allocate the stack first then the guard page.
+ *
+ * The stack is aligned to twice its size to facilitate overflow
+ * detection.
+ */
+ err = __create_hyp_private_mapping(__pa(stack_page), PAGE_SIZE,
+ PAGE_SIZE * 2, &stack_hyp_va, PAGE_HYP);
if (err) {
kvm_err("Cannot map hyp stack\n");
goto out_err;
}
+
+ /* Allocate unbacked private VA range for stack guard page */
+ guard_hyp_va = hyp_alloc_private_va_range(PAGE_SIZE, PAGE_SIZE);
+ if (IS_ERR((void *)guard_hyp_va)) {
+ err = PTR_ERR((void *)guard_hyp_va);
+ kvm_err("Cannot allocate hyp stack guard page\n");
+ goto out_err;
+ }
+
+ /*
+ * Save the stack PA in nvhe_init_params. This will be needed to recreate
+ * the stack mapping in protected nVHE mode. __hyp_pa() won't do the right
+ * thing there, since the stack has been mapped in the flexible private
+ * VA space.
+ */
+ params->stack_pa = __pa(stack_page) + PAGE_SIZE;
+
+ params->stack_hyp_va = stack_hyp_va + PAGE_SIZE;
}
for_each_possible_cpu(cpu) {
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> --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/arm.c | 32 +++++++++++++++++++++++++++++--- 2 files changed, 30 insertions(+), 3 deletions(-)