| Message ID | 20240227223501.28475-7-vikram.garhwal@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Xen: support grant mappings. | expand |
On Tue, 27 Feb 2024, Vikram Garhwal wrote: > From: Juergen Gross <jgross@suse.com> > > Add the callbacks for mapping/unmapping guest memory via grants to the > special grant memory region. > > Signed-off-by: Juergen Gross <jgross@suse.com> > Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > hw/xen/xen-mapcache.c | 176 +++++++++++++++++++++++++++++++++++++++++- > system/physmem.c | 11 ++- > 2 files changed, 182 insertions(+), 5 deletions(-) > > diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c > index 179b7e95b2..2e4c9b4947 100644 > --- a/hw/xen/xen-mapcache.c > +++ b/hw/xen/xen-mapcache.c > @@ -9,6 +9,8 @@ > */ > > #include "qemu/osdep.h" > +#include "qemu/queue.h" > +#include "qemu/thread.h" > #include "qemu/units.h" > #include "qemu/error-report.h" > > @@ -23,6 +25,8 @@ > #include "sysemu/xen-mapcache.h" > #include "trace.h" > > +#include <xenevtchn.h> > +#include <xengnttab.h> > > #if HOST_LONG_BITS == 32 > # define MCACHE_BUCKET_SHIFT 16 > @@ -377,7 +381,7 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, > return p; > } > > -ram_addr_t xen_ram_addr_from_mapcache(void *ptr) > +static ram_addr_t xen_ram_addr_from_mapcache_try(void *ptr) > { > MapCacheEntry *entry = NULL; > MapCacheRev *reventry; > @@ -588,10 +592,179 @@ uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr, > return p; > } > > +struct XENMappedGrantRegion { > + void *addr; > + unsigned int pages; > + unsigned int refs; > + unsigned int prot; > + uint32_t idx; > + QLIST_ENTRY(XENMappedGrantRegion) list; > +}; > + > +static xengnttab_handle *xen_region_gnttabdev; > +static QLIST_HEAD(GrantRegionList, XENMappedGrantRegion) xen_grant_mappings = > + QLIST_HEAD_INITIALIZER(xen_grant_mappings); > +static QemuMutex xen_map_mutex; > + > +static void *xen_map_grant_dyn(MemoryRegion **mr, hwaddr addr, hwaddr *plen, > + bool is_write, MemTxAttrs attrs) > +{ > + unsigned int page_off = addr & (XC_PAGE_SIZE - 1); > + unsigned int i; > + unsigned int total_grants = 0; > + unsigned int nrefs = (page_off + *plen + XC_PAGE_SIZE - 1) >> XC_PAGE_SHIFT; > + uint32_t ref = (addr - XEN_GRANT_ADDR_OFF) >> XC_PAGE_SHIFT; > + uint32_t *refs = NULL; > + unsigned int prot = PROT_READ; > + struct XENMappedGrantRegion *mgr = NULL; > + > + if (is_write) { > + prot |= PROT_WRITE; > + } > + > + qemu_mutex_lock(&xen_map_mutex); > + > + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { > + if (mgr->idx == ref && > + mgr->pages == nrefs && > + (mgr->prot & prot) == prot) { > + break; > + } > + > + total_grants += mgr->pages; > + } > + > + if (!mgr) { > + if (nrefs + total_grants >= XEN_MAX_VIRTIO_GRANTS) { > + qemu_mutex_unlock(&xen_map_mutex); > + return NULL; > + } > + > + mgr = g_new(struct XENMappedGrantRegion, 1); > + > + if (nrefs == 1) { > + refs = &ref; > + } else { > + refs = g_new(uint32_t, nrefs); > + for (i = 0; i < nrefs; i++) { > + refs[i] = ref + i; > + } > + } > + mgr->addr = xengnttab_map_domain_grant_refs(xen_region_gnttabdev, nrefs, > + xen_domid, refs, prot); > + if (mgr->addr) { > + mgr->pages = nrefs; > + mgr->refs = 1; > + mgr->prot = prot; > + mgr->idx = ref; > + > + QLIST_INSERT_HEAD(&xen_grant_mappings, mgr, list); > + } else { > + g_free(mgr); > + mgr = NULL; > + } > + } else { > + mgr->refs++; > + } > + > + qemu_mutex_unlock(&xen_map_mutex); > + > + if (nrefs > 1) { > + g_free(refs); > + } > + > + return mgr ? mgr->addr + page_off : NULL; > +} > + > +static void xen_unmap_grant_dyn(MemoryRegion *mr, void *buffer, ram_addr_t addr, > + hwaddr len, bool is_write, hwaddr access_len) > +{ > + unsigned int page_off = (unsigned long)buffer & (XC_PAGE_SIZE - 1); > + unsigned int nrefs = (page_off + len + XC_PAGE_SIZE - 1) >> XC_PAGE_SHIFT; > + unsigned int prot = PROT_READ; > + struct XENMappedGrantRegion *mgr = NULL; > + > + if (is_write) { > + prot |= PROT_WRITE; > + } > + > + qemu_mutex_lock(&xen_map_mutex); > + > + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { > + if (mgr->addr == buffer - page_off && > + mgr->pages == nrefs && > + (mgr->prot & prot) == prot) { > + break; > + } > + } > + if (mgr) { > + mgr->refs--; > + if (!mgr->refs) { > + xengnttab_unmap(xen_region_gnttabdev, mgr->addr, nrefs); > + > + QLIST_REMOVE(mgr, list); > + g_free(mgr); > + } > + } else { > + error_report("xen_unmap_grant_dyn() trying to unmap unknown buffer"); > + } > + > + qemu_mutex_unlock(&xen_map_mutex); > +} > + > +static ram_addr_t xen_ram_addr_from_grant_cache(void *ptr) > +{ > + unsigned int page_off = (unsigned long)ptr & (XC_PAGE_SIZE - 1); > + struct XENMappedGrantRegion *mgr = NULL; > + ram_addr_t raddr = RAM_ADDR_INVALID; > + > + qemu_mutex_lock(&xen_map_mutex); > + > + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { > + if (mgr->addr == ptr - page_off) { > + break; > + } > + } > + > + if (mgr) { > + raddr = (mgr->idx << XC_PAGE_SHIFT) + page_off + XEN_GRANT_ADDR_OFF; > + } > + > + qemu_mutex_unlock(&xen_map_mutex); > + > + return raddr; > +} > + > +ram_addr_t xen_ram_addr_from_mapcache(void *ptr) > +{ > + ram_addr_t raddr; > + > + raddr = xen_ram_addr_from_mapcache_try(ptr); > + if (raddr == RAM_ADDR_INVALID) { > + raddr = xen_ram_addr_from_grant_cache(ptr); > + } > + > + return raddr; > +} > + > +static const struct MemoryRegionOps xen_grant_mr_ops = { > + .map = xen_map_grant_dyn, > + .unmap = xen_unmap_grant_dyn, > + .endianness = DEVICE_LITTLE_ENDIAN, > +}; > + > MemoryRegion *xen_init_grant_ram(void) > { > RAMBlock *block; > > + qemu_mutex_init(&xen_map_mutex); > + > + xen_region_gnttabdev = xengnttab_open(NULL, 0); > + if (xen_region_gnttabdev == NULL) { > + fprintf(stderr, "can't open gnttab device\n"); > + return NULL; > + } > + > memory_region_init(&ram_grants, NULL, "xen.grants", > XEN_MAX_VIRTIO_GRANTS * XC_PAGE_SIZE); > block = g_malloc0(sizeof(*block)); > @@ -606,6 +779,7 @@ MemoryRegion *xen_init_grant_ram(void) > ram_grants.ram_block = block; > ram_grants.ram = true; > ram_grants.terminates = true; > + ram_grants.ops = &xen_grant_mr_ops; > ram_block_add_list(block); > memory_region_add_subregion(get_system_memory(), XEN_GRANT_ADDR_OFF, > &ram_grants); > diff --git a/system/physmem.c b/system/physmem.c > index d989e9fc1f..e6fc075d8f 100644 > --- a/system/physmem.c > +++ b/system/physmem.c > @@ -2232,13 +2232,16 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset, > > if (xen_enabled()) { > ram_addr_t ram_addr; > + > RCU_READ_LOCK_GUARD(); > ram_addr = xen_ram_addr_from_mapcache(ptr); > - block = qemu_get_ram_block(ram_addr); > - if (block) { > - *offset = ram_addr - block->offset; > + if (ram_addr != RAM_ADDR_INVALID) { > + block = qemu_get_ram_block(ram_addr); > + if (block) { > + *offset = ram_addr - block->offset; > + } > + return block; > } > - return block; > } > > RCU_READ_LOCK_GUARD(); > -- > 2.17.1 >
On Fri, Mar 1, 2024 at 12:34 AM Stefano Stabellini <sstabellini@kernel.org> wrote: > On Tue, 27 Feb 2024, Vikram Garhwal wrote: > > From: Juergen Gross <jgross@suse.com> > > > > Add the callbacks for mapping/unmapping guest memory via grants to the > > special grant memory region. > > > > Signed-off-by: Juergen Gross <jgross@suse.com> > > Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com> > > Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > > Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c index 179b7e95b2..2e4c9b4947 100644 --- a/hw/xen/xen-mapcache.c +++ b/hw/xen/xen-mapcache.c @@ -9,6 +9,8 @@ */ #include "qemu/osdep.h" +#include "qemu/queue.h" +#include "qemu/thread.h" #include "qemu/units.h" #include "qemu/error-report.h" @@ -23,6 +25,8 @@ #include "sysemu/xen-mapcache.h" #include "trace.h" +#include <xenevtchn.h> +#include <xengnttab.h> #if HOST_LONG_BITS == 32 # define MCACHE_BUCKET_SHIFT 16 @@ -377,7 +381,7 @@ uint8_t *xen_map_cache(hwaddr phys_addr, hwaddr size, return p; } -ram_addr_t xen_ram_addr_from_mapcache(void *ptr) +static ram_addr_t xen_ram_addr_from_mapcache_try(void *ptr) { MapCacheEntry *entry = NULL; MapCacheRev *reventry; @@ -588,10 +592,179 @@ uint8_t *xen_replace_cache_entry(hwaddr old_phys_addr, return p; } +struct XENMappedGrantRegion { + void *addr; + unsigned int pages; + unsigned int refs; + unsigned int prot; + uint32_t idx; + QLIST_ENTRY(XENMappedGrantRegion) list; +}; + +static xengnttab_handle *xen_region_gnttabdev; +static QLIST_HEAD(GrantRegionList, XENMappedGrantRegion) xen_grant_mappings = + QLIST_HEAD_INITIALIZER(xen_grant_mappings); +static QemuMutex xen_map_mutex; + +static void *xen_map_grant_dyn(MemoryRegion **mr, hwaddr addr, hwaddr *plen, + bool is_write, MemTxAttrs attrs) +{ + unsigned int page_off = addr & (XC_PAGE_SIZE - 1); + unsigned int i; + unsigned int total_grants = 0; + unsigned int nrefs = (page_off + *plen + XC_PAGE_SIZE - 1) >> XC_PAGE_SHIFT; + uint32_t ref = (addr - XEN_GRANT_ADDR_OFF) >> XC_PAGE_SHIFT; + uint32_t *refs = NULL; + unsigned int prot = PROT_READ; + struct XENMappedGrantRegion *mgr = NULL; + + if (is_write) { + prot |= PROT_WRITE; + } + + qemu_mutex_lock(&xen_map_mutex); + + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { + if (mgr->idx == ref && + mgr->pages == nrefs && + (mgr->prot & prot) == prot) { + break; + } + + total_grants += mgr->pages; + } + + if (!mgr) { + if (nrefs + total_grants >= XEN_MAX_VIRTIO_GRANTS) { + qemu_mutex_unlock(&xen_map_mutex); + return NULL; + } + + mgr = g_new(struct XENMappedGrantRegion, 1); + + if (nrefs == 1) { + refs = &ref; + } else { + refs = g_new(uint32_t, nrefs); + for (i = 0; i < nrefs; i++) { + refs[i] = ref + i; + } + } + mgr->addr = xengnttab_map_domain_grant_refs(xen_region_gnttabdev, nrefs, + xen_domid, refs, prot); + if (mgr->addr) { + mgr->pages = nrefs; + mgr->refs = 1; + mgr->prot = prot; + mgr->idx = ref; + + QLIST_INSERT_HEAD(&xen_grant_mappings, mgr, list); + } else { + g_free(mgr); + mgr = NULL; + } + } else { + mgr->refs++; + } + + qemu_mutex_unlock(&xen_map_mutex); + + if (nrefs > 1) { + g_free(refs); + } + + return mgr ? mgr->addr + page_off : NULL; +} + +static void xen_unmap_grant_dyn(MemoryRegion *mr, void *buffer, ram_addr_t addr, + hwaddr len, bool is_write, hwaddr access_len) +{ + unsigned int page_off = (unsigned long)buffer & (XC_PAGE_SIZE - 1); + unsigned int nrefs = (page_off + len + XC_PAGE_SIZE - 1) >> XC_PAGE_SHIFT; + unsigned int prot = PROT_READ; + struct XENMappedGrantRegion *mgr = NULL; + + if (is_write) { + prot |= PROT_WRITE; + } + + qemu_mutex_lock(&xen_map_mutex); + + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { + if (mgr->addr == buffer - page_off && + mgr->pages == nrefs && + (mgr->prot & prot) == prot) { + break; + } + } + if (mgr) { + mgr->refs--; + if (!mgr->refs) { + xengnttab_unmap(xen_region_gnttabdev, mgr->addr, nrefs); + + QLIST_REMOVE(mgr, list); + g_free(mgr); + } + } else { + error_report("xen_unmap_grant_dyn() trying to unmap unknown buffer"); + } + + qemu_mutex_unlock(&xen_map_mutex); +} + +static ram_addr_t xen_ram_addr_from_grant_cache(void *ptr) +{ + unsigned int page_off = (unsigned long)ptr & (XC_PAGE_SIZE - 1); + struct XENMappedGrantRegion *mgr = NULL; + ram_addr_t raddr = RAM_ADDR_INVALID; + + qemu_mutex_lock(&xen_map_mutex); + + QLIST_FOREACH(mgr, &xen_grant_mappings, list) { + if (mgr->addr == ptr - page_off) { + break; + } + } + + if (mgr) { + raddr = (mgr->idx << XC_PAGE_SHIFT) + page_off + XEN_GRANT_ADDR_OFF; + } + + qemu_mutex_unlock(&xen_map_mutex); + + return raddr; +} + +ram_addr_t xen_ram_addr_from_mapcache(void *ptr) +{ + ram_addr_t raddr; + + raddr = xen_ram_addr_from_mapcache_try(ptr); + if (raddr == RAM_ADDR_INVALID) { + raddr = xen_ram_addr_from_grant_cache(ptr); + } + + return raddr; +} + +static const struct MemoryRegionOps xen_grant_mr_ops = { + .map = xen_map_grant_dyn, + .unmap = xen_unmap_grant_dyn, + .endianness = DEVICE_LITTLE_ENDIAN, +}; + MemoryRegion *xen_init_grant_ram(void) { RAMBlock *block; + qemu_mutex_init(&xen_map_mutex); + + xen_region_gnttabdev = xengnttab_open(NULL, 0); + if (xen_region_gnttabdev == NULL) { + fprintf(stderr, "can't open gnttab device\n"); + return NULL; + } + memory_region_init(&ram_grants, NULL, "xen.grants", XEN_MAX_VIRTIO_GRANTS * XC_PAGE_SIZE); block = g_malloc0(sizeof(*block)); @@ -606,6 +779,7 @@ MemoryRegion *xen_init_grant_ram(void) ram_grants.ram_block = block; ram_grants.ram = true; ram_grants.terminates = true; + ram_grants.ops = &xen_grant_mr_ops; ram_block_add_list(block); memory_region_add_subregion(get_system_memory(), XEN_GRANT_ADDR_OFF, &ram_grants); diff --git a/system/physmem.c b/system/physmem.c index d989e9fc1f..e6fc075d8f 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -2232,13 +2232,16 @@ RAMBlock *qemu_ram_block_from_host(void *ptr, bool round_offset, if (xen_enabled()) { ram_addr_t ram_addr; + RCU_READ_LOCK_GUARD(); ram_addr = xen_ram_addr_from_mapcache(ptr); - block = qemu_get_ram_block(ram_addr); - if (block) { - *offset = ram_addr - block->offset; + if (ram_addr != RAM_ADDR_INVALID) { + block = qemu_get_ram_block(ram_addr); + if (block) { + *offset = ram_addr - block->offset; + } + return block; } - return block; } RCU_READ_LOCK_GUARD();