@@ -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;
@@ -116,6 +116,9 @@ alternative_cb_end
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
+extern struct kvm_pgtable *hyp_pgtable;
+extern struct mutex kvm_hyp_pgd_mutex;
+
void kvm_update_va_mask(struct alt_instr *alt,
__le32 *origptr, __le32 *updptr, int nr_inst);
void kvm_compute_layout(void);
@@ -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 +1989,49 @@ 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 hyp_addr;
+ /*
+ * 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.
+ */
+ hyp_addr = hyp_alloc_private_va_range(PAGE_SIZE * 2);
+ if (IS_ERR((void *)hyp_addr)) {
+ err = PTR_ERR((void *)hyp_addr);
+ kvm_err("Cannot allocate hyp stack guard page\n");
+ goto out_err;
+ }
+
+ /*
+ * 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.
+ */
+ mutex_lock(&kvm_hyp_pgd_mutex);
+ err = kvm_pgtable_hyp_map(hyp_pgtable, hyp_addr + PAGE_SIZE,
+ PAGE_SIZE, __pa(stack_page), PAGE_HYP);
+ mutex_unlock(&kvm_hyp_pgd_mutex);
if (err) {
kvm_err("Cannot map hyp stack\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);
+
+ params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
}
for_each_possible_cpu(cpu) {
@@ -22,8 +22,8 @@
#include "trace.h"
-static struct kvm_pgtable *hyp_pgtable;
-static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
+struct kvm_pgtable *hyp_pgtable;
+DEFINE_MUTEX(kvm_hyp_pgd_mutex);
static unsigned long hyp_idmap_start;
static unsigned long hyp_idmap_end;
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 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 hyp_alloc_private_va_range() returns an error for null pointer, per Fuad - Format comments to < 80 cols, per Fuad Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/include/asm/kvm_mmu.h | 3 +++ arch/arm64/kvm/arm.c | 40 +++++++++++++++++++++++++++++--- arch/arm64/kvm/mmu.c | 4 ++-- 4 files changed, 43 insertions(+), 5 deletions(-)