The Zicfilp extension adds the MLPE field to the mseccfg CSR. According to the RISC-V Privileged Specification, mseccfg exists if any extension that adds a field to it is implemented.
Currently, the `have_mseccfg()` predicate function checks for Smepmp, Zkr, and Smmpm, but misses Zicfilp. As a result, if a CPU is configured with `zicfilp=true` but without the other extensions, accessing the mseccfg CSR will incorrectly raise an illegal instruction exception. This patch adds the missing check for `ext_zicfilp` to ensure the CSR is properly accessible when the Zicfilp extension is enabled. This issue was discovered and reported by SpecHunter, an AI-driven architecture specification analysis tool. Link:https://github.com/yizishun/rv-isa-sec/blob/master/output/riscv-isa-manual/pr-2561/qemu.txt Signed-off-by: Zishun Yi <[email protected]> --- target/riscv/csr.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/target/riscv/csr.c b/target/riscv/csr.c index da366cf56271..40b17e773236 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -17,6 +17,7 @@ * this program. If not, see <http://www.gnu.org/licenses/>. */ +#include "cpu_bits.h" #include "qemu/osdep.h" #include "qemu/log.h" #include "qemu/timer.h" @@ -783,6 +784,9 @@ static RISCVException have_mseccfg(CPURISCVState *env, int csrno) if (riscv_cpu_cfg(env)->ext_smmpm) { return RISCV_EXCP_NONE; } + if (riscv_cpu_cfg(env)->ext_zicfilp) { + return RISCV_EXCP_NONE; + } return RISCV_EXCP_ILLEGAL_INST; } -- 2.51.2
