Re: [PATCH] target/riscv: Fix LCOFI masking in sie/sip/mvip

On 8/13/2026 10:40 AM, Mayuresh Chitale wrote:
> Commit 27f9566dcd98 ("target/riscv: Update the local interrupt mask")
> dropped bit 13 (MIP_LCOFIP) from the supervisor-visible interrupt masks.
> As a result, with Sscofpmf enabled and LCOFIP delegated to S-mode, the
> overflow interrupt would be raised in mip but never delivered and hence
> perf sampling stopped receiving overflow interrupts.
> 
> Re-add MIP_LCOFIP to all_ints, sip_writable_mask, mvip_writable_mask
> to allow it to be writable again.
> 
> Fixes: 27f9566dcd98 ("target/riscv: Update the local interrupt mask")
> Signed-off-by: Mayuresh Chitale <[email protected]>
> ---

Reviewed-by: Daniel Henrique Barboza <[email protected]>

>   target/riscv/tcg/csr.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/target/riscv/tcg/csr.c b/target/riscv/tcg/csr.c
> index c05c8ee076..ca68c1f5f1 100644
> --- a/target/riscv/tcg/csr.c
> +++ b/target/riscv/tcg/csr.c
> @@ -1890,7 +1890,8 @@ static const uint64_t delegable_ints =
>   static const uint64_t vs_delegable_ints =
>       (VS_MODE_INTERRUPTS | LOCAL_INTERRUPTS) & ~MIP_LCOFIP;
>   static const uint64_t all_ints = M_MODE_INTERRUPTS | S_MODE_INTERRUPTS |
> -                                     HS_MODE_INTERRUPTS | LOCAL_INTERRUPTS;
> +                                     HS_MODE_INTERRUPTS | MIP_LCOFIP |
> +                                     LOCAL_INTERRUPTS;
>   #define DELEGABLE_EXCPS ((1ULL << (RISCV_EXCP_INST_ADDR_MIS)) | \
>                            (1ULL << (RISCV_EXCP_INST_ACCESS_FAULT)) | \
>                            (1ULL << (RISCV_EXCP_ILLEGAL_INST)) | \
> @@ -1936,11 +1937,12 @@ static const target_ulong sstatus_v1_10_mask = SSTATUS_SIE | SSTATUS_SPIE |
>   
>   /* Bit STIP can be an alias of mip.STIP that's why it's writable in mvip. */
>   static const uint64_t mvip_writable_mask = MIP_SSIP | MIP_STIP | MIP_SEIP |
> -                                    LOCAL_INTERRUPTS;
> +                                    MIP_LCOFIP | LOCAL_INTERRUPTS;
>   static const uint64_t mvien_writable_mask = MIP_SSIP | MIP_SEIP |
>                                       LOCAL_INTERRUPTS;
>   
> -static const uint64_t sip_writable_mask = SIP_SSIP | LOCAL_INTERRUPTS;
> +static const uint64_t sip_writable_mask = SIP_SSIP | SIP_LCOFIP |
> +                                          LOCAL_INTERRUPTS;
>   static const uint64_t hip_writable_mask = MIP_VSSIP;
>   static const uint64_t hvip_writable_mask = MIP_VSSIP | MIP_VSTIP |
>                                       MIP_VSEIP | LOCAL_INTERRUPTS;
> @@ -3953,9 +3955,9 @@ static RISCVException rmw_mvip64(CPURISCVState *env, int csrno,
>        *  alias_mask denotes the bits that come from mip nalias_mask denotes bits
>        *  that come from hvip.
>        */
> -    uint64_t alias_mask = ((S_MODE_INTERRUPTS | LOCAL_INTERRUPTS) &
> +    uint64_t alias_mask = ((S_MODE_INTERRUPTS | MIP_LCOFIP | LOCAL_INTERRUPTS) &
>           (env->mideleg | ~env->mvien)) | MIP_STIP;
> -    uint64_t nalias_mask = (S_MODE_INTERRUPTS | LOCAL_INTERRUPTS) &
> +    uint64_t nalias_mask = (S_MODE_INTERRUPTS | MIP_LCOFIP | LOCAL_INTERRUPTS) &
>           (~env->mideleg & env->mvien);
>       uint64_t wr_mask_mvip;
>       uint64_t wr_mask_mip;
> @@ -4188,9 +4190,10 @@ static RISCVException rmw_sie64(CPURISCVState *env, int csrno,
>                                   uint64_t *ret_val,
>                                   uint64_t new_val, uint64_t wr_mask)
>   {
> -    uint64_t nalias_mask = (S_MODE_INTERRUPTS | LOCAL_INTERRUPTS) &
> +    uint64_t nalias_mask = (S_MODE_INTERRUPTS | MIP_LCOFIP | LOCAL_INTERRUPTS) &
>           (~env->mideleg & env->mvien);
> -    uint64_t alias_mask = (S_MODE_INTERRUPTS | LOCAL_INTERRUPTS) & env->mideleg;
> +    uint64_t alias_mask = (S_MODE_INTERRUPTS | MIP_LCOFIP | LOCAL_INTERRUPTS) &
> +        env->mideleg;
>       uint64_t sie_mask = wr_mask & nalias_mask;
>       RISCVException ret;
>