From f77c5f38f49c71bc14cf1019ac92b0b95f572414 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 17 Jan 2024 14:55:53 +0100 Subject: [PATCH] hv-balloon: use get_min_alignment() to express 32 GiB alignment Let's implement the get_min_alignment() callback for memory devices, and copy for the device memory region the alignment of the host memory region. This mimics what virtio-mem does, and allows for re-introducing proper alignment checks for the memory region size (where we don't care about additional device requirements) in memory device core. Message-ID: <20240117135554.787344-2-david@redhat.com> Reviewed-by: Maciej S. Szmigiero Signed-off-by: David Hildenbrand --- hw/hyperv/hv-balloon.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) diff --git a/hw/hyperv/hv-balloon.c b/hw/hyperv/hv-balloon.c index 0238365712..ade283335a 100644 --- a/hw/hyperv/hv-balloon.c +++ b/hw/hyperv/hv-balloon.c @@ -1477,22 +1477,7 @@ static void hv_balloon_ensure_mr(HvBalloon *balloon) balloon->mr = g_new0(MemoryRegion, 1); memory_region_init(balloon->mr, OBJECT(balloon), TYPE_HV_BALLOON, memory_region_size(hostmem_mr)); - - /* - * The VM can indicate an alignment up to 32 GiB. Memory device core can - * usually only handle/guarantee 1 GiB alignment. The user will have to - * specify a larger maxmem eventually. - * - * The memory device core will warn the user in case maxmem might have to be - * increased and will fail plugging the device if there is not sufficient - * space after alignment. - * - * TODO: we could do the alignment ourselves in a slightly bigger region. - * But this feels better, although the warning might be annoying. Maybe - * we can optimize that in the future (e.g., with such a device on the - * cmdline place/size the device memory region differently. - */ - balloon->mr->align = MAX(32 * GiB, memory_region_get_alignment(hostmem_mr)); + balloon->mr->align = memory_region_get_alignment(hostmem_mr); } static void hv_balloon_free_mr(HvBalloon *balloon) @@ -1654,6 +1639,25 @@ static MemoryRegion *hv_balloon_md_get_memory_region(MemoryDeviceState *md, return balloon->mr; } +static uint64_t hv_balloon_md_get_min_alignment(const MemoryDeviceState *md) +{ + /* + * The VM can indicate an alignment up to 32 GiB. Memory device core can + * usually only handle/guarantee 1 GiB alignment. The user will have to + * specify a larger maxmem eventually. + * + * The memory device core will warn the user in case maxmem might have to be + * increased and will fail plugging the device if there is not sufficient + * space after alignment. + * + * TODO: we could do the alignment ourselves in a slightly bigger region. + * But this feels better, although the warning might be annoying. Maybe + * we can optimize that in the future (e.g., with such a device on the + * cmdline place/size the device memory region differently. + */ + return 32 * GiB; +} + static void hv_balloon_md_fill_device_info(const MemoryDeviceState *md, MemoryDeviceInfo *info) { @@ -1766,5 +1770,6 @@ static void hv_balloon_class_init(ObjectClass *klass, void *data) mdc->get_memory_region = hv_balloon_md_get_memory_region; mdc->decide_memslots = hv_balloon_decide_memslots; mdc->get_memslots = hv_balloon_get_memslots; + mdc->get_min_alignment = hv_balloon_md_get_min_alignment; mdc->fill_device_info = hv_balloon_md_fill_device_info; } -- 2.30.2