On Fri, Mar 1, 2024 at 12:11 AM Stefano Stabellini <sstabell...@kernel.org>
wrote:
> On Tue, 27 Feb 2024, Vikram Garhwal wrote:
> > From: Juergen Gross <jgr...@suse.com>
> >
> > In order to support mapping and unmapping guest memory dynamically to
> > and from qemu during address_space_[un]map() operations add the map()
> > and unmap() callbacks to MemoryRegionOps.
> >
> > Those will be used e.g. for Xen grant mappings when performing guest
> > I/Os.
> >
> > Signed-off-by: Juergen Gross <jgr...@suse.com>
> > Signed-off-by: Vikram Garhwal <vikram.garh...@amd.com>
>
> Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
>
Reviewed-by: Edgar E. Iglesias <edgar.igles...@amd.com>
> ---
> > include/exec/memory.h | 21 ++++++++++++++++++
> > system/physmem.c | 50 +++++++++++++++++++++++++++++++++----------
> > 2 files changed, 60 insertions(+), 11 deletions(-)
> >
> > diff --git a/include/exec/memory.h b/include/exec/memory.h
> > index 8626a355b3..9f7dfe59c7 100644
> > --- a/include/exec/memory.h
> > +++ b/include/exec/memory.h
> > @@ -282,6 +282,27 @@ struct MemoryRegionOps {
> > unsigned size,
> > MemTxAttrs attrs);
> >
> > + /*
> > + * Dynamically create mapping. @addr is the guest address to map;
> @plen
> > + * is the pointer to the usable length of the buffer.
> > + * @mr contents can be changed in case a new memory region is
> created for
> > + * the mapping.
> > + * Returns the buffer address for accessing the data.
> > + */
> > + void *(*map)(MemoryRegion **mr,
> > + hwaddr addr,
> > + hwaddr *plen,
> > + bool is_write,
> > + MemTxAttrs attrs);
> > +
> > + /* Unmap an area obtained via map() before. */
> > + void (*unmap)(MemoryRegion *mr,
> > + void *buffer,
> > + ram_addr_t addr,
> > + hwaddr len,
> > + bool is_write,
> > + hwaddr access_len);
> > +
> > enum device_endian endianness;
> > /* Guest-visible constraints: */
> > struct {
> > diff --git a/system/physmem.c b/system/physmem.c
> > index 949dcb20ba..d989e9fc1f 100644
> > --- a/system/physmem.c
> > +++ b/system/physmem.c
> > @@ -3141,6 +3141,7 @@ void *address_space_map(AddressSpace *as,
> > hwaddr len = *plen;
> > hwaddr l, xlat;
> > MemoryRegion *mr;
> > + void *ptr = NULL;
> > FlatView *fv;
> >
> > if (len == 0) {
> > @@ -3174,12 +3175,20 @@ void *address_space_map(AddressSpace *as,
> > return bounce.buffer;
> > }
> >
> > -
> > memory_region_ref(mr);
> > +
> > + if (mr->ops && mr->ops->map) {
> > + ptr = mr->ops->map(&mr, addr, plen, is_write, attrs);
> > + }
> > +
> > *plen = flatview_extend_translation(fv, addr, len, mr, xlat,
> > l, is_write, attrs);
> > fuzz_dma_read_cb(addr, *plen, mr);
> > - return qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
> > + if (ptr == NULL) {
> > + ptr = qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
> > + }
> > +
> > + return ptr;
> > }
> >
> > /* Unmaps a memory region previously mapped by address_space_map().
> > @@ -3195,11 +3204,16 @@ void address_space_unmap(AddressSpace *as, void
> *buffer, hwaddr len,
> >
> > mr = memory_region_from_host(buffer, &addr1);
> > assert(mr != NULL);
> > - if (is_write) {
> > - invalidate_and_set_dirty(mr, addr1, access_len);
> > - }
> > - if (xen_enabled()) {
> > - xen_invalidate_map_cache_entry(buffer);
> > +
> > + if (mr->ops && mr->ops->unmap) {
> > + mr->ops->unmap(mr, buffer, addr1, len, is_write,
> access_len);
> > + } else {
> > + if (is_write) {
> > + invalidate_and_set_dirty(mr, addr1, access_len);
> > + }
> > + if (xen_enabled()) {
> > + xen_invalidate_map_cache_entry(buffer);
> > + }
> > }
> > memory_region_unref(mr);
> > return;
> > @@ -3272,10 +3286,18 @@ int64_t
> address_space_cache_init(MemoryRegionCache *cache,
> > * doing this if we found actual RAM, which behaves the same
> > * regardless of attributes; so UNSPECIFIED is fine.
> > */
> > + if (mr->ops && mr->ops->map) {
> > + cache->ptr = mr->ops->map(&mr, addr, &l, is_write,
> > + MEMTXATTRS_UNSPECIFIED);
> > + }
> > +
> > l = flatview_extend_translation(cache->fv, addr, len, mr,
> > cache->xlat, l, is_write,
> > MEMTXATTRS_UNSPECIFIED);
> > - cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat,
> &l, true);
> > + if (!cache->ptr) {
> > + cache->ptr = qemu_ram_ptr_length(mr->ram_block,
> cache->xlat, &l,
> > + true);
> > + }
> > } else {
> > cache->ptr = NULL;
> > }
> > @@ -3297,14 +3319,20 @@ void
> address_space_cache_invalidate(MemoryRegionCache *cache,
> >
> > void address_space_cache_destroy(MemoryRegionCache *cache)
> > {
> > - if (!cache->mrs.mr) {
> > + MemoryRegion *mr = cache->mrs.mr;
> > +
> > + if (!mr) {
> > return;
> > }
> >
> > - if (xen_enabled()) {
> > + if (mr->ops && mr->ops->unmap) {
> > + mr->ops->unmap(mr, cache->ptr, cache->xlat, cache->len,
> > + cache->is_write, cache->len);
> > + } else if (xen_enabled()) {
> > xen_invalidate_map_cache_entry(cache->ptr);
> > }
> > - memory_region_unref(cache->mrs.mr);
> > +
> > + memory_region_unref(mr);
> > flatview_unref(cache->fv);
> > cache->mrs.mr = NULL;
> > cache->fv = NULL;
> > --
> > 2.17.1
> >
>
>
