On Thu, Feb 17, 2022 at 1:49 AM Christoph Muellner <cmuell...@linux.com> wrote:
>
> The existing probe_access* functions do not allow to specify the
> access size and a non-faulting behavior at the same time.
>
> This is resolved by adding a generalization of probe_access_flags()
> that takes an additional size parameter.
>
> The semantics is basically the same as probe_access_flags(),
> but instead of assuming an access to any byte of the addressed
> page, we can restrict to access to a specific area, like
> probe_access() allows.
>
> Signed-off-by: Christoph Muellner <cmuell...@linux.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> accel/tcg/cputlb.c | 17 +++++++++++++----
> accel/tcg/user-exec.c | 15 ++++++++++++---
> include/exec/exec-all.h | 24 ++++++++++++++++++++++++
> 3 files changed, 49 insertions(+), 7 deletions(-)
>
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index 5e0d0eebc3..b4f0eb20b0 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -1624,13 +1624,14 @@ static int probe_access_internal(CPUArchState *env,
> target_ulong addr,
> return flags;
> }
>
> -int probe_access_flags(CPUArchState *env, target_ulong addr,
> - MMUAccessType access_type, int mmu_idx,
> - bool nonfault, void **phost, uintptr_t retaddr)
> +int probe_access_range_flags(CPUArchState *env, target_ulong addr,
> + int size, MMUAccessType access_type,
> + int mmu_idx, bool nonfault, void **phost,
> + uintptr_t retaddr)
> {
> int flags;
>
> - flags = probe_access_internal(env, addr, 0, access_type, mmu_idx,
> + flags = probe_access_internal(env, addr, size, access_type, mmu_idx,
> nonfault, phost, retaddr);
>
> /* Handle clean RAM pages. */
> @@ -1645,6 +1646,14 @@ int probe_access_flags(CPUArchState *env, target_ulong
> addr,
> return flags;
> }
>
> +int probe_access_flags(CPUArchState *env, target_ulong addr,
> + MMUAccessType access_type, int mmu_idx,
> + bool nonfault, void **phost, uintptr_t retaddr)
> +{
> + return probe_access_range_flags(env, addr, 0, access_type, mmu_idx,
> + nonfault, phost, retaddr);
> +}
> +
> void *probe_access(CPUArchState *env, target_ulong addr, int size,
> MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
> {
> diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
> index 6f5d4933f0..0dbc345e63 100644
> --- a/accel/tcg/user-exec.c
> +++ b/accel/tcg/user-exec.c
> @@ -176,9 +176,10 @@ static int probe_access_internal(CPUArchState *env,
> target_ulong addr,
> cpu_loop_exit_sigsegv(env_cpu(env), addr, access_type, maperr, ra);
> }
>
> -int probe_access_flags(CPUArchState *env, target_ulong addr,
> - MMUAccessType access_type, int mmu_idx,
> - bool nonfault, void **phost, uintptr_t ra)
> +int probe_access_range_flags(CPUArchState *env, target_ulong addr,
> + int size, MMUAccessType access_type,
> + int mmu_idx, bool nonfault, void **phost,
> + uintptr_t ra)
> {
> int flags;
>
> @@ -187,6 +188,14 @@ int probe_access_flags(CPUArchState *env, target_ulong
> addr,
> return flags;
> }
>
> +int probe_access_flags(CPUArchState *env, target_ulong addr,
> + MMUAccessType access_type, int mmu_idx,
> + bool nonfault, void **phost, uintptr_t ra)
> +{
> + return probe_access_range_flags(env, addr, 0, access_type, mmu_idx,
> + nonfault, phost, ra);
> +}
> +
> void *probe_access(CPUArchState *env, target_ulong addr, int size,
> MMUAccessType access_type, int mmu_idx, uintptr_t ra)
> {
> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> index 35d8e93976..0d06b45c62 100644
> --- a/include/exec/exec-all.h
> +++ b/include/exec/exec-all.h
> @@ -441,6 +441,30 @@ static inline void *probe_read(CPUArchState *env,
> target_ulong addr, int size,
> return probe_access(env, addr, size, MMU_DATA_LOAD, mmu_idx, retaddr);
> }
>
> +/**
> + * probe_access_range_flags:
> + * @env: CPUArchState
> + * @addr: guest virtual address to look up
> + * @size: size of the access
> + * @access_type: read, write or execute permission
> + * @mmu_idx: MMU index to use for lookup
> + * @nonfault: suppress the fault
> + * @phost: return value for host address
> + * @retaddr: return address for unwinding
> + *
> + * Similar to probe_access, loosely returning the TLB_FLAGS_MASK for
> + * the access range, and storing the host address for RAM in @phost.
> + *
> + * If @nonfault is set, do not raise an exception but return
> TLB_INVALID_MASK.
> + * Do not handle watchpoints, but include TLB_WATCHPOINT in the returned
> flags.
> + * Do handle clean pages, so exclude TLB_NOTDIRY from the returned flags.
> + * For simplicity, all "mmio-like" flags are folded to TLB_MMIO.
> + */
> +int probe_access_range_flags(CPUArchState *env, target_ulong addr,
> + int size, MMUAccessType access_type,
> + int mmu_idx, bool nonfault, void **phost,
> + uintptr_t retaddr);
> +
> /**
> * probe_access_flags:
> * @env: CPUArchState
> --
> 2.35.1
>
>
