On Mon, Aug 23, 2021 at 06:41:56PM +0200, Philippe Mathieu-Daudé wrote: > Introduce flatview_access_allowed() to check bus permission > before running any bus transaction. For now this is a simple > stub. > > Signed-off-by: Philippe Mathieu-Daudé <[email protected]> > --- > softmmu/physmem.c | 37 +++++++++++++++++++++++++++++++++++-- > 1 file changed, 35 insertions(+), 2 deletions(-) > > diff --git a/softmmu/physmem.c b/softmmu/physmem.c > index e534dc69918..0d31a2f4199 100644 > --- a/softmmu/physmem.c > +++ b/softmmu/physmem.c > @@ -2754,6 +2754,27 @@ static bool prepare_mmio_access(MemoryRegion *mr) > return release_lock; > } > > +/** > + * flatview_access_allowed > + * @mr: #MemoryRegion to be accessed > + * @attrs: memory transaction attributes > + * @addr: address within that memory region > + * @len: the number of bytes to access > + * @result: optional pointer to a MemTxResult or NULL > + * > + * Check if a memory transaction is allowed. If an error occurs this > + * method will return false to indicate denial, as well as setting > + * @result to contain corresponding #MemTxResult. > + * > + * Returns: true if transaction is allowed, false if denied. > + */ > +static inline bool flatview_access_allowed(MemoryRegion *mr, MemTxAttrs > attrs, > + hwaddr addr, hwaddr len, > + MemTxResult *result) > +{ > + return true; > +}
The callers below don't benefit from the result pointer argument. The
code would be clearer if they did:
if (!flatview_access_allowed(...)) {
return MEMTX_BUS_ERROR;
}
> +
> /* Called within RCU critical section. */
> static MemTxResult flatview_write_continue(FlatView *fv, hwaddr addr,
> MemTxAttrs attrs,
> @@ -2768,7 +2789,9 @@ static MemTxResult flatview_write_continue(FlatView
> *fv, hwaddr addr,
> const uint8_t *buf = ptr;
>
> for (;;) {
> - if (!memory_access_is_direct(mr, true)) {
> + if (!flatview_access_allowed(mr, attrs, addr1, l, &result)) {
> + /* 'result' contains the error, keep going. */
> + } else if (!memory_access_is_direct(mr, true)) {
> release_lock |= prepare_mmio_access(mr);
> l = memory_access_size(mr, l, addr1);
> /* XXX: could force current_cpu to NULL to avoid
> @@ -2810,9 +2833,13 @@ static MemTxResult flatview_write(FlatView *fv, hwaddr
> addr, MemTxAttrs attrs,
> hwaddr l;
> hwaddr addr1;
> MemoryRegion *mr;
> + MemTxResult result = MEMTX_OK;
>
> l = len;
> mr = flatview_translate(fv, addr, &addr1, &l, true, attrs);
> + if (!flatview_access_allowed(mr, attrs, addr, len, &result)) {
> + return result;
> + }
> return flatview_write_continue(fv, addr, attrs, buf, len,
> addr1, l, mr);
> }
> @@ -2831,7 +2858,9 @@ MemTxResult flatview_read_continue(FlatView *fv, hwaddr
> addr,
>
> fuzz_dma_read_cb(addr, len, mr);
> for (;;) {
> - if (!memory_access_is_direct(mr, false)) {
> + if (!flatview_access_allowed(mr, attrs, addr1, l, &result)) {
> + /* 'result' contains the error, keep going. */
> + } else if (!memory_access_is_direct(mr, false)) {
> /* I/O case */
> release_lock |= prepare_mmio_access(mr);
> l = memory_access_size(mr, l, addr1);
> @@ -2871,9 +2900,13 @@ static MemTxResult flatview_read(FlatView *fv, hwaddr
> addr,
> hwaddr l;
> hwaddr addr1;
> MemoryRegion *mr;
> + MemTxResult result = MEMTX_OK;
>
> l = len;
> mr = flatview_translate(fv, addr, &addr1, &l, false, attrs);
> + if (!flatview_access_allowed(mr, attrs, addr, len, &result)) {
> + return result;
> + }
> return flatview_read_continue(fv, addr, attrs, buf, len,
> addr1, l, mr);
> }
> --
> 2.31.1
>
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