--- /dev/null
+From 310227f42882c52356b523e2f4e11690eebcd2ab Mon Sep 17 00:00:00 2001
+From: David Hildenbrand <david@redhat.com>
+Date: Tue, 13 Feb 2024 14:54:25 +0100
+Subject: virtio: reenable config if freezing device failed
+
+From: David Hildenbrand <david@redhat.com>
+
+commit 310227f42882c52356b523e2f4e11690eebcd2ab upstream.
+
+Currently, we don't reenable the config if freezing the device failed.
+
+For example, virtio-mem currently doesn't support suspend+resume, and
+trying to freeze the device will always fail. Afterwards, the device
+will no longer respond to resize requests, because it won't get notified
+about config changes.
+
+Let's fix this by re-enabling the config if freezing fails.
+
+Fixes: 22b7050a024d ("virtio: defer config changed notifications")
+Cc: <stable@kernel.org>
+Cc: "Michael S. Tsirkin" <mst@redhat.com>
+Cc: Jason Wang <jasowang@redhat.com>
+Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
+Signed-off-by: David Hildenbrand <david@redhat.com>
+Message-Id: <20240213135425.795001-1-david@redhat.com>
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/virtio/virtio.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+--- a/drivers/virtio/virtio.c
++++ b/drivers/virtio/virtio.c
+@@ -455,13 +455,19 @@ EXPORT_SYMBOL_GPL(unregister_virtio_devi
+ int virtio_device_freeze(struct virtio_device *dev)
+ {
+ struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
++ int ret;
+
+ virtio_config_disable(dev);
+
+ dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
+
+- if (drv && drv->freeze)
+- return drv->freeze(dev);
++ if (drv && drv->freeze) {
++ ret = drv->freeze(dev);
++ if (ret) {
++ virtio_config_enable(dev);
++ return ret;
++ }
++ }
+
+ return 0;
+ }
--- /dev/null
+From 04c35ab3bdae7fefbd7c7a7355f29fa03a035221 Mon Sep 17 00:00:00 2001
+From: David Hildenbrand <david@redhat.com>
+Date: Wed, 3 Apr 2024 23:21:30 +0200
+Subject: x86/mm/pat: fix VM_PAT handling in COW mappings
+
+From: David Hildenbrand <david@redhat.com>
+
+commit 04c35ab3bdae7fefbd7c7a7355f29fa03a035221 upstream.
+
+PAT handling won't do the right thing in COW mappings: the first PTE (or,
+in fact, all PTEs) can be replaced during write faults to point at anon
+folios. Reliably recovering the correct PFN and cachemode using
+follow_phys() from PTEs will not work in COW mappings.
+
+Using follow_phys(), we might just get the address+protection of the anon
+folio (which is very wrong), or fail on swap/nonswap entries, failing
+follow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and
+track_pfn_copy(), not properly calling free_pfn_range().
+
+In free_pfn_range(), we either wouldn't call memtype_free() or would call
+it with the wrong range, possibly leaking memory.
+
+To fix that, let's update follow_phys() to refuse returning anon folios,
+and fallback to using the stored PFN inside vma->vm_pgoff for COW mappings
+if we run into that.
+
+We will now properly handle untrack_pfn() with COW mappings, where we
+don't need the cachemode. We'll have to fail fork()->track_pfn_copy() if
+the first page was replaced by an anon folio, though: we'd have to store
+the cachemode in the VMA to make this work, likely growing the VMA size.
+
+For now, lets keep it simple and let track_pfn_copy() just fail in that
+case: it would have failed in the past with swap/nonswap entries already,
+and it would have done the wrong thing with anon folios.
+
+Simple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():
+
+<--- C reproducer --->
+ #include <stdio.h>
+ #include <sys/mman.h>
+ #include <unistd.h>
+ #include <liburing.h>
+
+ int main(void)
+ {
+ struct io_uring_params p = {};
+ int ring_fd;
+ size_t size;
+ char *map;
+
+ ring_fd = io_uring_setup(1, &p);
+ if (ring_fd < 0) {
+ perror("io_uring_setup");
+ return 1;
+ }
+ size = p.sq_off.array + p.sq_entries * sizeof(unsigned);
+
+ /* Map the submission queue ring MAP_PRIVATE */
+ map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
+ ring_fd, IORING_OFF_SQ_RING);
+ if (map == MAP_FAILED) {
+ perror("mmap");
+ return 1;
+ }
+
+ /* We have at least one page. Let's COW it. */
+ *map = 0;
+ pause();
+ return 0;
+ }
+<--- C reproducer --->
+
+On a system with 16 GiB RAM and swap configured:
+ # ./iouring &
+ # memhog 16G
+ # killall iouring
+[ 301.552930] ------------[ cut here ]------------
+[ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100
+[ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g
+[ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1
+[ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4
+[ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100
+[ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000
+[ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282
+[ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047
+[ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200
+[ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000
+[ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000
+[ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000
+[ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000
+[ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+[ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0
+[ 301.565725] PKRU: 55555554
+[ 301.565944] Call Trace:
+[ 301.566148] <TASK>
+[ 301.566325] ? untrack_pfn+0xf4/0x100
+[ 301.566618] ? __warn+0x81/0x130
+[ 301.566876] ? untrack_pfn+0xf4/0x100
+[ 301.567163] ? report_bug+0x171/0x1a0
+[ 301.567466] ? handle_bug+0x3c/0x80
+[ 301.567743] ? exc_invalid_op+0x17/0x70
+[ 301.568038] ? asm_exc_invalid_op+0x1a/0x20
+[ 301.568363] ? untrack_pfn+0xf4/0x100
+[ 301.568660] ? untrack_pfn+0x65/0x100
+[ 301.568947] unmap_single_vma+0xa6/0xe0
+[ 301.569247] unmap_vmas+0xb5/0x190
+[ 301.569532] exit_mmap+0xec/0x340
+[ 301.569801] __mmput+0x3e/0x130
+[ 301.570051] do_exit+0x305/0xaf0
+...
+
+Link: https://lkml.kernel.org/r/20240403212131.929421-3-david@redhat.com
+Signed-off-by: David Hildenbrand <david@redhat.com>
+Reported-by: Wupeng Ma <mawupeng1@huawei.com>
+Closes: https://lkml.kernel.org/r/20240227122814.3781907-1-mawupeng1@huawei.com
+Fixes: b1a86e15dc03 ("x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines")
+Fixes: 5899329b1910 ("x86: PAT: implement track/untrack of pfnmap regions for x86 - v3")
+Acked-by: Ingo Molnar <mingo@kernel.org>
+Cc: Dave Hansen <dave.hansen@linux.intel.com>
+Cc: Andy Lutomirski <luto@kernel.org>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Cc: Borislav Petkov <bp@alien8.de>
+Cc: "H. Peter Anvin" <hpa@zytor.com>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: David Hildenbrand <david@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/mm/pat/memtype.c | 49 ++++++++++++++++++++++++++++++++--------------
+ mm/memory.c | 4 +++
+ 2 files changed, 39 insertions(+), 14 deletions(-)
+
+--- a/arch/x86/mm/pat/memtype.c
++++ b/arch/x86/mm/pat/memtype.c
+@@ -989,6 +989,38 @@ static void free_pfn_range(u64 paddr, un
+ memtype_free(paddr, paddr + size);
+ }
+
++static int get_pat_info(struct vm_area_struct *vma, resource_size_t *paddr,
++ pgprot_t *pgprot)
++{
++ unsigned long prot;
++
++ VM_WARN_ON_ONCE(!(vma->vm_flags & VM_PAT));
++
++ /*
++ * We need the starting PFN and cachemode used for track_pfn_remap()
++ * that covered the whole VMA. For most mappings, we can obtain that
++ * information from the page tables. For COW mappings, we might now
++ * suddenly have anon folios mapped and follow_phys() will fail.
++ *
++ * Fallback to using vma->vm_pgoff, see remap_pfn_range_notrack(), to
++ * detect the PFN. If we need the cachemode as well, we're out of luck
++ * for now and have to fail fork().
++ */
++ if (!follow_phys(vma, vma->vm_start, 0, &prot, paddr)) {
++ if (pgprot)
++ *pgprot = __pgprot(prot);
++ return 0;
++ }
++ if (is_cow_mapping(vma->vm_flags)) {
++ if (pgprot)
++ return -EINVAL;
++ *paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
++ return 0;
++ }
++ WARN_ON_ONCE(1);
++ return -EINVAL;
++}
++
+ /*
+ * track_pfn_copy is called when vma that is covering the pfnmap gets
+ * copied through copy_page_range().
+@@ -999,20 +1031,13 @@ static void free_pfn_range(u64 paddr, un
+ int track_pfn_copy(struct vm_area_struct *vma)
+ {
+ resource_size_t paddr;
+- unsigned long prot;
+ unsigned long vma_size = vma->vm_end - vma->vm_start;
+ pgprot_t pgprot;
+
+ if (vma->vm_flags & VM_PAT) {
+- /*
+- * reserve the whole chunk covered by vma. We need the
+- * starting address and protection from pte.
+- */
+- if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+- WARN_ON_ONCE(1);
++ if (get_pat_info(vma, &paddr, &pgprot))
+ return -EINVAL;
+- }
+- pgprot = __pgprot(prot);
++ /* reserve the whole chunk covered by vma. */
+ return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
+ }
+
+@@ -1087,7 +1112,6 @@ void untrack_pfn(struct vm_area_struct *
+ unsigned long size)
+ {
+ resource_size_t paddr;
+- unsigned long prot;
+
+ if (vma && !(vma->vm_flags & VM_PAT))
+ return;
+@@ -1095,11 +1119,8 @@ void untrack_pfn(struct vm_area_struct *
+ /* free the chunk starting from pfn or the whole chunk */
+ paddr = (resource_size_t)pfn << PAGE_SHIFT;
+ if (!paddr && !size) {
+- if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+- WARN_ON_ONCE(1);
++ if (get_pat_info(vma, &paddr, NULL))
+ return;
+- }
+-
+ size = vma->vm_end - vma->vm_start;
+ }
+ free_pfn_range(paddr, size);
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -5086,6 +5086,10 @@ int follow_phys(struct vm_area_struct *v
+ goto out;
+ pte = *ptep;
+
++ /* Never return PFNs of anon folios in COW mappings. */
++ if (vm_normal_page(vma, address, pte))
++ goto unlock;
++
+ if ((flags & FOLL_WRITE) && !pte_write(pte))
+ goto unlock;
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
