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[Qemu-riscv] [PATCHv3 1/5] RISC-V: Only Check PMP if MMU translation suc

From: Hesham Almatary
Subject: [Qemu-riscv] [PATCHv3 1/5] RISC-V: Only Check PMP if MMU translation succeeds
Date: Wed, 22 May 2019 10:09:47 +0100

The current implementation unnecessarily checks for PMP even if MMU translation
failed. This may trigger a wrong PMP access exception instead of
a page exception.

For example, the very first instruction fetched after the first satp write in
S-Mode will trigger a PMP access fault instead of an instruction fetch page

This patch prioritises MMU exceptions over PMP exceptions and only checks for
PMP if MMU translation succeeds. This patch is required for future commits
that properly report PMP exception violations if PTW succeeds.

Signed-off-by: Hesham Almatary <address@hidden>
 target/riscv/cpu_helper.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 41d6db41c3..40fb47e794 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -401,6 +401,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int 
                   " prot %d\n", __func__, address, ret, pa, prot);

     if (riscv_feature(env, RISCV_FEATURE_PMP) &&
+        (ret == TRANSLATE_SUCCESS) &&
         !pmp_hart_has_privs(env, pa, TARGET_PAGE_SIZE, 1 << access_type)) {
         ret = TRANSLATE_FAIL;

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