[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 3/4] xen/mapcache: introduce xen_replace_cache_entry()
On Tue, 4 Jul 2017, Igor Druzhinin wrote: > This new call is trying to update a requested map cache entry > according to the changes in the physmap. The call is searching > for the entry, unmaps it and maps again at the same place using > a new guest address. If the mapping is dummy this call will > make it real. > > This function makes use of a new xenforeignmemory_map2() call > with an extended interface that was recently introduced in > libxenforeignmemory [1]. > > [1] https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxx/msg113007.html > > Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx> > --- > configure | 18 ++++++++++ > hw/i386/xen/xen-mapcache.c | 79 > ++++++++++++++++++++++++++++++++++++++----- > include/hw/xen/xen_common.h | 7 ++++ > include/sysemu/xen-mapcache.h | 11 +++++- > 4 files changed, 106 insertions(+), 9 deletions(-) > > diff --git a/configure b/configure > index c571ad1..ad6156b 100755 > --- a/configure > +++ b/configure > @@ -2021,6 +2021,24 @@ EOF > # Xen unstable > elif > cat > $TMPC <<EOF && > +#undef XC_WANT_COMPAT_MAP_FOREIGN_API > +#include <xenforeignmemory.h> > +int main(void) { > + xenforeignmemory_handle *xfmem; > + > + xfmem = xenforeignmemory_open(0, 0); > + xenforeignmemory_map2(xfmem, 0, 0, 0, 0, 0, 0, 0); > + > + return 0; > +} > +EOF > + compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs" > + then > + xen_stable_libs="-lxendevicemodel $xen_stable_libs" > + xen_ctrl_version=41000 > + xen=yes > + elif > + cat > $TMPC <<EOF && > #undef XC_WANT_COMPAT_DEVICEMODEL_API > #define __XEN_TOOLS__ > #include <xendevicemodel.h> > diff --git a/hw/i386/xen/xen-mapcache.c b/hw/i386/xen/xen-mapcache.c > index cd4e746..a988be7 100644 > --- a/hw/i386/xen/xen-mapcache.c > +++ b/hw/i386/xen/xen-mapcache.c > @@ -151,6 +151,7 @@ void xen_map_cache_init(phys_offset_to_gaddr_t f, void > *opaque) > } > > static void xen_remap_bucket(MapCacheEntry *entry, > + void *vaddr, > hwaddr size, > hwaddr address_index, > bool dummy) > @@ -167,7 +168,9 @@ static void xen_remap_bucket(MapCacheEntry *entry, > err = g_malloc0(nb_pfn * sizeof (int)); > > if (entry->vaddr_base != NULL) { > - ram_block_notify_remove(entry->vaddr_base, entry->size); > + if (entry->vaddr_base != vaddr) { > + ram_block_notify_remove(entry->vaddr_base, entry->size); > + } I would prefer to see checks based on the dummy flag, rather than entry->vaddr_base != vaddr. > if (munmap(entry->vaddr_base, entry->size) != 0) { > perror("unmap fails"); > exit(-1); > @@ -181,11 +184,11 @@ static void xen_remap_bucket(MapCacheEntry *entry, > } > > if (!dummy) { > - vaddr_base = xenforeignmemory_map(xen_fmem, xen_domid, > - PROT_READ|PROT_WRITE, > + vaddr_base = xenforeignmemory_map2(xen_fmem, xen_domid, vaddr, > + PROT_READ|PROT_WRITE, 0, > nb_pfn, pfns, err); > if (vaddr_base == NULL) { > - perror("xenforeignmemory_map"); > + perror("xenforeignmemory_map2"); > exit(-1); > } Can we print a warning if (!dummy && vaddr != NULL)? > entry->flags &= ~(XEN_MAPCACHE_ENTRY_DUMMY); > @@ -194,7 +197,7 @@ static void xen_remap_bucket(MapCacheEntry *entry, > * We create dummy mappings where we are unable to create a foreign > * mapping immediately due to certain circumstances (i.e. on resume > now) > */ > - vaddr_base = mmap(NULL, size, PROT_READ|PROT_WRITE, > + vaddr_base = mmap(vaddr, size, PROT_READ|PROT_WRITE, > MAP_ANON|MAP_SHARED, -1, 0); > if (vaddr_base == NULL) { > perror("mmap"); > @@ -203,13 +206,16 @@ static void xen_remap_bucket(MapCacheEntry *entry, > entry->flags |= XEN_MAPCACHE_ENTRY_DUMMY; > } > > + if (entry->vaddr_base == NULL || entry->vaddr_base != vaddr) { > + ram_block_notify_add(vaddr_base, size); > + } Please also check (or check instead) on the dummy flag. > entry->vaddr_base = vaddr_base; > entry->paddr_index = address_index; > entry->size = size; > entry->valid_mapping = (unsigned long *) g_malloc0(sizeof(unsigned long) > * > BITS_TO_LONGS(size >> XC_PAGE_SHIFT)); > > - ram_block_notify_add(entry->vaddr_base, entry->size); > bitmap_zero(entry->valid_mapping, nb_pfn); > for (i = 0; i < nb_pfn; i++) { > if (!err[i]) { > @@ -282,14 +288,14 @@ tryagain: > if (!entry) { > entry = g_malloc0(sizeof (MapCacheEntry)); > pentry->next = entry; > - xen_remap_bucket(entry, cache_size, address_index, dummy); > + xen_remap_bucket(entry, NULL, cache_size, address_index, dummy); > } else if (!entry->lock) { > if (!entry->vaddr_base || entry->paddr_index != address_index || > entry->size != cache_size || > !test_bits(address_offset >> XC_PAGE_SHIFT, > test_bit_size >> XC_PAGE_SHIFT, > entry->valid_mapping)) { > - xen_remap_bucket(entry, cache_size, address_index, dummy); > + xen_remap_bucket(entry, NULL, cache_size, address_index, dummy); > } > } > > @@ -486,3 +492,60 @@ void xen_invalidate_map_cache(void) > > mapcache_unlock(); > } > + > +static uint8_t *xen_replace_cache_entry_unlocked(hwaddr old_phys_addr, > + hwaddr new_phys_addr, > + hwaddr size) > +{ > + MapCacheEntry *entry; > + hwaddr address_index; > + hwaddr address_offset; > + hwaddr cache_size = size; > + hwaddr test_bit_size; > + > + address_index = old_phys_addr >> MCACHE_BUCKET_SHIFT; > + address_offset = old_phys_addr & (MCACHE_BUCKET_SIZE - 1); > + > + assert(size); > + /* test_bit_size is always a multiple of XC_PAGE_SIZE */ > + test_bit_size = size + (old_phys_addr & (XC_PAGE_SIZE - 1)); > + if (test_bit_size % XC_PAGE_SIZE) { > + test_bit_size += XC_PAGE_SIZE - (test_bit_size % XC_PAGE_SIZE); > + } > + cache_size = size + address_offset; > + if (cache_size % MCACHE_BUCKET_SIZE) { > + cache_size += MCACHE_BUCKET_SIZE - (cache_size % MCACHE_BUCKET_SIZE); > + } > + > + entry = &mapcache->entry[address_index % mapcache->nr_buckets]; > + while (entry && !(entry->paddr_index == address_index && entry->size == > cache_size)) { > + entry = entry->next; > + } > + if (!entry) { > + DPRINTF("Trying to update an entry for %lx that is not in the > mapcache!\n", phys_addr); > + return NULL; > + } > + > + address_index = new_phys_addr >> MCACHE_BUCKET_SHIFT; > + address_offset = new_phys_addr & (MCACHE_BUCKET_SIZE - 1); > + > + xen_remap_bucket(entry, entry->vaddr_base, cache_size, address_index, > false); > + if(!test_bits(address_offset >> XC_PAGE_SHIFT, > + test_bit_size >> XC_PAGE_SHIFT, > + entry->valid_mapping)) { > + DPRINTF("Unable to update an entry for %lx in the mapcache!\n", > phys_addr); > + return NULL; > + } > + return entry->vaddr_base + address_offset; > +} > + > +uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr, hwaddr new_phys_addr, > hwaddr size) > +{ > + uint8_t *p; > + > + mapcache_lock(); > + p = xen_replace_cache_entry_unlocked(old_phys_addr, new_phys_addr, size); > + mapcache_unlock(); > + return p; > +} > diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h > index e00ddd7..70a5cad 100644 > --- a/include/hw/xen/xen_common.h > +++ b/include/hw/xen/xen_common.h > @@ -78,6 +78,13 @@ static inline void *xenforeignmemory_map(xc_interface *h, > uint32_t dom, > > extern xenforeignmemory_handle *xen_fmem; > > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41000 > + > +#define xenforeignmemory_map2(h, d, a, p, f, ps, ar, e) \ > + xenforeignmemory_map(h, d, p, ps, ar, e) > + > +#endif > + > #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900 > > typedef xc_interface xendevicemodel_handle; > diff --git a/include/sysemu/xen-mapcache.h b/include/sysemu/xen-mapcache.h > index 01daaad..b38962c 100644 > --- a/include/sysemu/xen-mapcache.h > +++ b/include/sysemu/xen-mapcache.h > @@ -21,7 +21,9 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, > ram_addr_t xen_ram_addr_from_mapcache(void *ptr); > void xen_invalidate_map_cache_entry(uint8_t *buffer); > void xen_invalidate_map_cache(void); > - > +uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr, > + hwaddr new_phys_addr, > + hwaddr size); > #else > > static inline void xen_map_cache_init(phys_offset_to_gaddr_t f, > @@ -50,6 +52,13 @@ static inline void xen_invalidate_map_cache(void) > { > } > > +uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr, > + hwaddr new_phys_addr, > + hwaddr size) > +{ > + abort(); > +} > + > #endif > > #endif /* XEN_MAPCACHE_H */ > -- > 2.7.4 > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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