From: Alistair Francis <alistair.francis@wdc.com>
Since commit 4047368938f6 "accel/tcg: Introduce tlb_set_page_full" we
have been seeing this assert
../accel/tcg/cputlb.c:1294: tlb_set_page_with_attrs: Assertion
`is_power_of_2(size)' failed.
When running Tock on the OpenTitan machine.
The issue is that pmp_get_tlb_size() would return a TLB size that wasn't
a power of 2. The size was also smaller then TARGET_PAGE_SIZE.
This patch ensures that any TLB size less then TARGET_PAGE_SIZE is
rounded down to 1 to ensure it's a valid size.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
This is based on advice from Richard:
https://patchwork.kernel.org/project/qemu-devel/patch/20221004141051.110653-9-richard.henderson@linaro.org/#25043166
target/riscv/pmp.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index ea2b67d947..2b43e399b8 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -628,6 +628,18 @@ bool pmp_is_range_in_tlb(CPURISCVState *env, hwaddr tlb_sa,
}
if (*tlb_size != 0) {
+ /*
+ * At this point we have a tlb_size that is the smallest possible size
+ * That fits within a TARGET_PAGE_SIZE and the PMP region.
+ *
+ * If the size is less then TARGET_PAGE_SIZE we drop the size to 1.
+ * This means the result isn't cached in the TLB and is only used for
+ * a single translation.
+ */
+ if (*tlb_size < TARGET_PAGE_SIZE) {
+ *tlb_size = 1;
+ }
+
return true;
}