From: Nitesh Narayan Lal <nilal@xxxxxxxxxx> This patch enables QEMU to handle page hinting requests from the guest. Once the guest kicks QEMU to free a list of page, QEMU retrives the guest physical address in the list and converts each to host virtual address and then MADVISE that memory. Signed-off-by: Nitesh Narayan Lal <nilal@xxxxxxxxxx> --- hw/virtio/virtio-balloon.c | 117 +++++++++++++++++++++++- hw/virtio/virtio.c | 23 +++++ include/hw/virtio/virtio-access.h | 1 + include/hw/virtio/virtio-balloon.h | 2 +- include/qemu/osdep.h | 7 ++ include/standard-headers/linux/virtio_balloon.h | 1 + 6 files changed, 149 insertions(+), 2 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index 1f7a87f..46deacb 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -34,6 +34,8 @@ #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) +void page_hinting_request(uint64_t addr, uint32_t len); + static void balloon_page(void *addr, int deflate) { if (!qemu_balloon_is_inhibited() && (!kvm_enabled() || @@ -77,11 +79,22 @@ static bool balloon_stats_supported(const VirtIOBalloon *s) return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); } +static bool balloon_hinting_supported(const VirtIOBalloon *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + return virtio_vdev_has_feature(vdev, VIRTIO_GUEST_PAGE_HINTING_VQ); +} + static bool balloon_stats_enabled(const VirtIOBalloon *s) { return s->stats_poll_interval > 0; } +static bool page_hinting_enabled(const VirtIOBalloon *s) +{ + return s->stats_poll_interval > 0; +} + static void balloon_stats_destroy_timer(VirtIOBalloon *s) { if (balloon_stats_enabled(s)) { @@ -97,14 +110,20 @@ static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); } +static void page_hinting_change_timer(VirtIOBalloon *s, int64_t secs) +{ + timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); +} + static void balloon_stats_poll_cb(void *opaque) { VirtIOBalloon *s = opaque; VirtIODevice *vdev = VIRTIO_DEVICE(s); - if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { + if (s->stats_vq_elem == NULL || !balloon_stats_supported(s) || !balloon_hinting_supported(s)) { /* re-schedule */ balloon_stats_change_timer(s, s->stats_poll_interval); + page_hinting_change_timer(s, s->stats_poll_interval); return; } @@ -201,12 +220,101 @@ static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, balloon_stats_change_timer(s, value); return; } + + if (page_hinting_enabled(s)) { + /* timer interval change */ + s->stats_poll_interval = value; + page_hinting_change_timer(s, value); + return; + } /* create a new timer */ g_assert(s->stats_timer == NULL); s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); s->stats_poll_interval = value; balloon_stats_change_timer(s, 0); + /* create a new timer */ + g_assert(s->stats_timer == NULL); + s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); + s->stats_poll_interval = value; + page_hinting_change_timer(s, 0); +} + +static void *gpa2hva(MemoryRegion **p_mr, hwaddr addr, Error **errp) +{ + MemoryRegionSection mrs = memory_region_find(get_system_memory(), + addr, 1); + + if (!mrs.mr) { + error_setg(errp, "No memory is mapped at address 0x%" HWADDR_PRIx, addr); + return NULL; + } + + if (!memory_region_is_ram(mrs.mr) && !memory_region_is_romd(mrs.mr)) { + error_setg(errp, "Memory at address 0x%" HWADDR_PRIx "is not RAM", addr); + memory_region_unref(mrs.mr); + return NULL; + } + + *p_mr = mrs.mr; + return qemu_map_ram_ptr(mrs.mr->ram_block, mrs.offset_within_region); +} + +struct guest_pages { + unsigned long pfn; + unsigned int pages; +}; + + +void page_hinting_request(uint64_t addr, uint32_t len) +{ + Error *local_err = NULL; + MemoryRegion *mr = NULL; + void *hvaddr; + int ret = 0; + struct guest_pages *guest_obj; + int i = 0; + void *hvaddr_to_free; + unsigned long pfn, pfn_end; + uint64_t gpaddr_to_free; + + hvaddr = gpa2hva(&mr, addr, &local_err); + if (local_err) { + error_report_err(local_err); + return; + } + guest_obj = hvaddr; + + while (i < len) { + pfn = guest_obj[i].pfn; + pfn_end = guest_obj[i].pfn + guest_obj[i].pages - 1; + while (pfn <= pfn_end) { + gpaddr_to_free = pfn << VIRTIO_BALLOON_PFN_SHIFT; + hvaddr_to_free = gpa2hva(&mr, gpaddr_to_free, &local_err); + if (local_err) { + error_report_err(local_err); + return; + } + ret = qemu_madvise((void *)hvaddr_to_free, 4096, QEMU_MADV_FREE); + if (ret == -1) + printf("\n%d:%s Error: Madvise failed with error:%d\n", __LINE__, __func__, ret); + pfn++; + } + i++; + } +} + + +static void virtio_balloon_page_hinting(VirtIODevice *vdev, VirtQueue *vq) +{ + uint64_t addr; + uint32_t len; + VirtQueueElement elem = {}; + + pop_hinting_addr(vq, &addr, &len); + page_hinting_request(addr, len); + virtqueue_push(vq, &elem, 0); + virtio_notify(vdev, vq); } static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) @@ -379,6 +487,7 @@ static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); f |= dev->host_features; virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); + virtio_add_feature(&f, VIRTIO_GUEST_PAGE_HINTING_VQ); return f; } @@ -412,6 +521,9 @@ static int virtio_balloon_post_load_device(void *opaque, int version_id) if (balloon_stats_enabled(s)) { balloon_stats_change_timer(s, s->stats_poll_interval); } + if (page_hinting_enabled(s)) { + page_hinting_change_timer(s, s->stats_poll_interval); + } return 0; } @@ -448,6 +560,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); + s->hvq = virtio_add_queue(vdev, 128, virtio_balloon_page_hinting); reset_stats(s); } @@ -491,6 +604,8 @@ static void virtio_balloon_instance_init(Object *obj) object_property_add(obj, "guest-stats", "guest statistics", balloon_stats_get_all, NULL, NULL, s, NULL); + object_property_add(obj, "guest-page-hinting", "guest page hinting", + NULL, NULL, NULL, s, NULL); object_property_add(obj, "guest-stats-polling-interval", "int", balloon_stats_get_poll_interval, diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 1debb01..11ddc13 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -825,6 +825,29 @@ static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_nu return elem; } +void pop_hinting_addr(VirtQueue *vq, uint64_t *addr, uint32_t *len) +{ + VRingMemoryRegionCaches *caches; + VRingDesc desc; + MemoryRegionCache *desc_cache; + VirtIODevice *vdev = vq->vdev; + unsigned int head, max; + + max = vq->vring.num; + if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) { + printf("\n%d:%sError: Unable to read head\n", __LINE__, __func__); + } + + caches = vring_get_region_caches(vq); + if (caches->desc.len < max * sizeof(VRingDesc)) { + virtio_error(vdev, "Cannot map descriptor ring"); + } + desc_cache = &caches->desc; + vring_desc_read(vdev, &desc, desc_cache, head); + *addr = desc.addr; + *len = desc.len; +} + void *virtqueue_pop(VirtQueue *vq, size_t sz) { unsigned int i, head, max; diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h index 2e92074..568d71f 100644 --- a/include/hw/virtio/virtio-access.h +++ b/include/hw/virtio/virtio-access.h @@ -24,6 +24,7 @@ #define LEGACY_VIRTIO_IS_BIENDIAN 1 #endif +void pop_hinting_addr(VirtQueue *vq, uint64_t *addr, uint32_t *len); static inline bool virtio_access_is_big_endian(VirtIODevice *vdev) { #if defined(LEGACY_VIRTIO_IS_BIENDIAN) diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-balloon.h index e0df352..774498a 100644 --- a/include/hw/virtio/virtio-balloon.h +++ b/include/hw/virtio/virtio-balloon.h @@ -32,7 +32,7 @@ typedef struct virtio_balloon_stat_modern { typedef struct VirtIOBalloon { VirtIODevice parent_obj; - VirtQueue *ivq, *dvq, *svq; + VirtQueue *ivq, *dvq, *svq, *hvq; uint32_t num_pages; uint32_t actual; uint64_t stats[VIRTIO_BALLOON_S_NR]; diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 4165806..dc62f17 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -305,6 +305,11 @@ void qemu_anon_ram_free(void *ptr, size_t size); #else #define QEMU_MADV_REMOVE QEMU_MADV_INVALID #endif +#ifdef MADV_FREE +#define QEMU_MADV_FREE MADV_FREE +#else +#define QEMU_MADV_FREE QEMU_MADV_INVALID +#endif #elif defined(CONFIG_POSIX_MADVISE) @@ -318,6 +323,7 @@ void qemu_anon_ram_free(void *ptr, size_t size); #define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID #define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID #define QEMU_MADV_REMOVE QEMU_MADV_INVALID +#define QEMU_MADV_FREE QEMU_MADV_INVALID #else /* no-op */ @@ -331,6 +337,7 @@ void qemu_anon_ram_free(void *ptr, size_t size); #define QEMU_MADV_HUGEPAGE QEMU_MADV_INVALID #define QEMU_MADV_NOHUGEPAGE QEMU_MADV_INVALID #define QEMU_MADV_REMOVE QEMU_MADV_INVALID +#define QEMU_MADV_FREE QEMU_MADV_INVALID #endif diff --git a/include/standard-headers/linux/virtio_balloon.h b/include/standard-headers/linux/virtio_balloon.h index e446805..1372da1 100644 --- a/include/standard-headers/linux/virtio_balloon.h +++ b/include/standard-headers/linux/virtio_balloon.h @@ -34,6 +34,7 @@ #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */ #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ +#define VIRTIO_GUEST_PAGE_HINTING_VQ 3 /* Page hinting virtqueue */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12 -- 2.9.5