From 6f8be29ec17d44496b9ed67599bceaaba72d1864 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 1 May 2023 19:04:09 -0400 Subject: vhost-user: send SET_STATUS 0 after GET_VRING_BASE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Setting the VIRTIO Device Status Field to 0 resets the device. The device's state is lost, including the vring configuration. vhost-user.c currently sends SET_STATUS 0 before GET_VRING_BASE. This risks confusion about the lifetime of the vhost-user state (e.g. vring last_avail_idx) across VIRTIO device reset. Eugenio Pérez adjusted the order for vhost-vdpa.c in commit c3716f260bff ("vdpa: move vhost reset after get vring base") and in that commit description suggested doing the same for vhost-user in the future. Go ahead and adjust vhost-user.c now. I ran various online code searches to identify vhost-user backends implementing SET_STATUS. It seems only DPDK implements SET_STATUS and Yajun Wu has confirmed that it is safe to make this change. Fixes: commit 923b8921d210763359e96246a58658ac0db6c645 ("vhost-user: Support vhost_dev_start") Cc: Michael S. Tsirkin Cc: Cindy Lu Cc: Yajun Wu Signed-off-by: Stefan Hajnoczi Message-Id: <20230501230409.274178-1-stefanha@redhat.com> Reviewed-by: Maxime Coquelin Reviewed-by: Yajun Wu  Acked-by: Eugenio Pérez Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/vhost-user.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'hw/virtio/vhost-user.c') diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index e5285df4ba..40974afd06 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -2677,7 +2677,20 @@ static int vhost_user_dev_start(struct vhost_dev *dev, bool started) VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK); } else { - return vhost_user_set_status(dev, 0); + return 0; + } +} + +static void vhost_user_reset_status(struct vhost_dev *dev) +{ + /* Set device status only for last queue pair */ + if (dev->vq_index + dev->nvqs != dev->vq_index_end) { + return; + } + + if (virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_STATUS)) { + vhost_user_set_status(dev, 0); } } @@ -2716,4 +2729,5 @@ const VhostOps user_ops = { .vhost_get_inflight_fd = vhost_user_get_inflight_fd, .vhost_set_inflight_fd = vhost_user_set_inflight_fd, .vhost_dev_start = vhost_user_dev_start, + .vhost_reset_status = vhost_user_reset_status, }; -- cgit 1.4.1 From bab105300bdeb7b651dd1b1f666ecb8e44be6d71 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 3 May 2023 20:41:44 +0200 Subject: vhost-user: Remove acpi-specific memslot limit Let's just support 512 memslots on x86-64 and aarch64 as well. The maximum number of ACPI slots (256) is no longer completely expressive ever since we supported virtio-based memory devices. Further, we're completely ignoring other memslots used outside of memory device context, such as memslots used for boot memory. Note that the vhost memslot limit in the kernel is usually configured to be 509. With this change, we prepare vhost-user on the QEMU side to be closer to that limit, to eventually support ~512 memslots in most vhost implementations and have less "surprises" when cold/hotplugging vhost devices while also consuming more memslots than we're currently used to by memory devices (e.g., once virtio-mem starts using multiple memslots). Note that most vhost-user implementations only support a small number of memslots so far, which we can hopefully improve in the near future. We'll leave the PPC special-case as is for now. Cc: "Michael S. Tsirkin" Cc: Igor Mammedov Cc: Stefan Hajnoczi Signed-off-by: David Hildenbrand Message-Id: <20230503184144.808478-1-david@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/vhost-user.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) (limited to 'hw/virtio/vhost-user.c') diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 40974afd06..e3ec8727da 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -42,17 +42,7 @@ #define VHOST_USER_F_PROTOCOL_FEATURES 30 #define VHOST_USER_BACKEND_MAX_FDS 8 -/* - * Set maximum number of RAM slots supported to - * the maximum number supported by the target - * hardware plaform. - */ -#if defined(TARGET_X86) || defined(TARGET_X86_64) || \ - defined(TARGET_ARM) || defined(TARGET_AARCH64) -#include "hw/acpi/acpi.h" -#define VHOST_USER_MAX_RAM_SLOTS ACPI_MAX_RAM_SLOTS - -#elif defined(TARGET_PPC) || defined(TARGET_PPC64) +#if defined(TARGET_PPC) || defined(TARGET_PPC64) #include "hw/ppc/spapr.h" #define VHOST_USER_MAX_RAM_SLOTS SPAPR_MAX_RAM_SLOTS -- cgit 1.4.1