[Qemu-riscv] [PULL 08/32] RISC-V: Check PMP during Page Table Walks

[Palmer Dabbelt]

From: Hesham Almatary <address@hidden>

The PMP should be checked when doing a page table walk, and report access
fault exception if the to-be-read PTE failed the PMP check.

Suggested-by: Jonathan Behrens <address@hidden>
Signed-off-by: Hesham Almatary <address@hidden>
Reviewed-by: Palmer Dabbelt <address@hidden>
Signed-off-by: Palmer Dabbelt <address@hidden>
---
 target/riscv/cpu.h        |  1 +
 target/riscv/cpu_helper.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 2e743312536b..934b71c85e13 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -81,6 +81,7 @@ enum {
 #define PRIV_VERSION_1_09_1 0x00010901
 #define PRIV_VERSION_1_10_0 0x00011000
 
+#define TRANSLATE_PMP_FAIL 2
 #define TRANSLATE_FAIL 1
 #define TRANSLATE_SUCCESS 0
 #define MMU_USER_IDX 3
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 71b8123b1019..66be83210f11 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -230,6 +230,12 @@ restart:
 
         /* check that physical address of PTE is legal */
         target_ulong pte_addr = base + idx * ptesize;
+
+        if (riscv_feature(env, RISCV_FEATURE_PMP) &&
+            !pmp_hart_has_privs(env, pte_addr, sizeof(target_ulong),
+            1 << MMU_DATA_LOAD, PRV_S)) {
+            return TRANSLATE_PMP_FAIL;
+        }
 #if defined(TARGET_RISCV32)
         target_ulong pte = ldl_phys(cs->as, pte_addr);
 #elif defined(TARGET_RISCV64)
@@ -448,8 +454,10 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int 
size,
         (ret == TRANSLATE_SUCCESS) &&
         !pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type,
         mode)) {
+        ret = TRANSLATE_PMP_FAIL;
+    }
+    if (ret == TRANSLATE_PMP_FAIL) {
         pmp_violation = true;
-        ret = TRANSLATE_FAIL;
     }
     if (ret == TRANSLATE_SUCCESS) {
         tlb_set_page(cs, address & TARGET_PAGE_MASK, pa & TARGET_PAGE_MASK,
-- 
2.21.0