[PATCH] sbi: sbi_domain_context: Fix trap context for domain context switching

[Anup Patel]

On Fri, Jun 7, 2024 at 5:09 PM Yu Chien Peter Lin
<peterlin at andestech.com> wrote:
>
> Save/restore sbi_trap_context during domain context switching to
> ensure proper trap handling and isolation. This maintains correct
> domain-specific state, avoiding context corruption.
>
> Fixes: abea949721bc ("lib: sbi: Introduce trap context")
> Signed-off-by: Yu Chien Peter Lin <peterlin at andestech.com>
> Reviewed-by: Alvin Chang <alvinga at andestech.com>
> Tested-by: Alvin Chang <alvinga at andestech.com>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  include/sbi/sbi_domain_context.h | 2 +-
>  lib/sbi/sbi_domain_context.c     | 9 ++++-----
>  2 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/include/sbi/sbi_domain_context.h b/include/sbi/sbi_domain_context.h
> index edba764f..0d25884a 100755
> --- a/include/sbi/sbi_domain_context.h
> +++ b/include/sbi/sbi_domain_context.h
> @@ -14,7 +14,7 @@
>  /** Context representation for a hart within a domain */
>  struct sbi_context {
>         /** Trap-related states such as GPRs, mepc, and mstatus */
> -       struct sbi_trap_regs regs;
> +       struct sbi_trap_context trap_ctx;
>
>         /** Supervisor status register */
>         unsigned long sstatus;
> diff --git a/lib/sbi/sbi_domain_context.c b/lib/sbi/sbi_domain_context.c
> index 75285918..49a2f769 100755
> --- a/lib/sbi/sbi_domain_context.c
> +++ b/lib/sbi/sbi_domain_context.c
> @@ -27,7 +27,7 @@ static void switch_to_next_domain_context(struct sbi_context *ctx,
>                                           struct sbi_context *dom_ctx)
>  {
>         u32 hartindex = sbi_hartid_to_hartindex(current_hartid());
> -       struct sbi_trap_regs *trap_regs;
> +       struct sbi_trap_context *trap_ctx;
>         struct sbi_domain *current_dom = ctx->dom;
>         struct sbi_domain *target_dom = dom_ctx->dom;
>         struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
> @@ -66,10 +66,9 @@ static void switch_to_next_domain_context(struct sbi_context *ctx,
>                 ctx->senvcfg    = csr_swap(CSR_SENVCFG, dom_ctx->senvcfg);
>
>         /* Save current trap state and restore target domain's trap state */
> -       trap_regs = (struct sbi_trap_regs *)(csr_read(CSR_MSCRATCH) -
> -                                            SBI_TRAP_REGS_SIZE);
> -       sbi_memcpy(&ctx->regs, trap_regs, sizeof(*trap_regs));
> -       sbi_memcpy(trap_regs, &dom_ctx->regs, sizeof(*trap_regs));
> +       trap_ctx = sbi_trap_get_context(scratch);
> +       sbi_memcpy(&ctx->trap_ctx, trap_ctx, sizeof(*trap_ctx));
> +       sbi_memcpy(trap_ctx, &dom_ctx->trap_ctx, sizeof(*trap_ctx));
>
>         /* Mark current context structure initialized because context saved */
>         ctx->initialized = true;
> --
> 2.34.1
>