From b430b51395650137a80e78ee7395165b80fe1752 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 16 Nov 2020 11:59:47 +0100 Subject: util/vfio-helpers.c: Use ram_block_discard_disable() in qemu_vfio_open_pci() Currently, when using "nvme://" for a block device, like -drive file=nvme://0000:01:00.0/1,if=none,id=drive0 \ -device virtio-blk,drive=drive0 \ VFIO may pin all guest memory, and discarding of RAM no longer works as expected. I was able to reproduce this easily with my 01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983 Similar to common VFIO, we have to disable it, making sure that: a) virtio-balloon won't discard any memory ("silently disabled") b) virtio-mem and nvme:// run mutually exclusive Cc: Paolo Bonzini Cc: "Michael S. Tsirkin" Cc: Alex Williamson Cc: Wei Yang Cc: Dr. David Alan Gilbert Cc: Igor Mammedov Cc: Pankaj Gupta Cc: Peter Xu Signed-off-by: David Hildenbrand Message-Id: <20201116105947.9194-1-david@redhat.com> Signed-off-by: Paolo Bonzini --- util/vfio-helpers.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'util') diff --git a/util/vfio-helpers.c b/util/vfio-helpers.c index c469beb061..2bec48e163 100644 --- a/util/vfio-helpers.c +++ b/util/vfio-helpers.c @@ -16,6 +16,7 @@ #include "qapi/error.h" #include "exec/ramlist.h" #include "exec/cpu-common.h" +#include "exec/memory.h" #include "trace.h" #include "qemu/error-report.h" #include "standard-headers/linux/pci_regs.h" @@ -494,8 +495,20 @@ QEMUVFIOState *qemu_vfio_open_pci(const char *device, Error **errp) int r; QEMUVFIOState *s = g_new0(QEMUVFIOState, 1); + /* + * VFIO may pin all memory inside mappings, resulting it in pinning + * all memory inside RAM blocks unconditionally. + */ + r = ram_block_discard_disable(true); + if (r) { + error_setg_errno(errp, -r, "Cannot set discarding of RAM broken"); + g_free(s); + return NULL; + } + r = qemu_vfio_init_pci(s, device, errp); if (r) { + ram_block_discard_disable(false); g_free(s); return NULL; } @@ -837,4 +850,5 @@ void qemu_vfio_close(QEMUVFIOState *s) close(s->device); close(s->group); close(s->container); + ram_block_discard_disable(false); } -- cgit v1.2.3