On Wed, Sep 13, 2023 at 11:50:58PM -0400, Xiaoyao Li wrote:
> From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
>
> Add KVM gmem support to RAMBlock so both normal hva based memory
> and kvm gmem fd based private memory can be associated in one RAMBlock.
>
> Introduce new flag RAM_KVM_GMEM. It calls KVM ioctl to create private
> gmem for the RAMBlock when it's set.
>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
> ---
> accel/kvm/kvm-all.c | 17 +++++++++++++++++
> include/exec/memory.h | 3 +++
> include/exec/ramblock.h | 1 +
> include/sysemu/kvm.h | 2 ++
> softmmu/physmem.c | 18 +++++++++++++++---
> 5 files changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 60aacd925393..185ae16d9620 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -4225,3 +4225,20 @@ void query_stats_schemas_cb(StatsSchemaList **result, Error **errp)
> query_stats_schema_vcpu(first_cpu, &stats_args);
> }
> }
> +
> +int kvm_create_guest_memfd(uint64_t size, uint64_t flags, Error **errp)
> +{
> + int fd;
> + struct kvm_create_guest_memfd gmem = {
> + .size = size,
> + /* TODO: to decide whether KVM_GUEST_MEMFD_ALLOW_HUGEPAGE is supported */
> + .flags = flags,
> + };
> +
> + fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_GUEST_MEMFD, &gmem);
> + if (fd < 0) {
> + error_setg_errno(errp, errno, "%s: error creating kvm gmem\n", __func__);
> + }
> +
> + return fd;
> +}
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 68284428f87c..227cb2578e95 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -235,6 +235,9 @@ typedef struct IOMMUTLBEvent {
> /* RAM is an mmap-ed named file */
> #define RAM_NAMED_FILE (1 << 9)
>
> +/* RAM can be private that has kvm gmem backend */
> +#define RAM_KVM_GMEM (1 << 10)
> +
> static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
> IOMMUNotifierFlag flags,
> hwaddr start, hwaddr end,
> diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h
> index 69c6a5390293..0d158b3909c9 100644
> --- a/include/exec/ramblock.h
> +++ b/include/exec/ramblock.h
> @@ -41,6 +41,7 @@ struct RAMBlock {
> QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
> int fd;
> uint64_t fd_offset;
> + int gmem_fd;
> size_t page_size;
> /* dirty bitmap used during migration */
> unsigned long *bmap;
You're adding a file descriptor to RAMBlock, but I don't see
anything in this patch that ever calls close(gmem_fd) when the
RAMBlock is released. Presuambly reclaim_ramblock() needs to
deal with this ?
With regards,
Daniel
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