Xen 4.16.4-pre-patchset-04.16.4-pre-patchset-0

Signed-off-by: Tomáš Mózes <hydrapolic@gmail.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/0029-x86-perform-mem_sharing-teardown-before-paging-teard.patch b/0029-x86-perform-mem_sharing-teardown-before-paging-teard.patch
new file mode 100644
index 0000000..c96f44e
--- /dev/null
+++ b/0029-x86-perform-mem_sharing-teardown-before-paging-teard.patch
@@ -0,0 +1,111 @@
+From 700320a79297fb5087f7dd540424c468b2d2cffe Mon Sep 17 00:00:00 2001
+From: Tamas K Lengyel <tamas@tklengyel.com>
+Date: Fri, 3 Mar 2023 08:14:25 +0100
+Subject: [PATCH 29/61] x86: perform mem_sharing teardown before paging
+ teardown
+
+An assert failure has been observed in p2m_teardown when performing vm
+forking and then destroying the forked VM (p2m-basic.c:173). The assert
+checks whether the domain's shared pages counter is 0. According to the
+patch that originally added the assert (7bedbbb5c31) the p2m_teardown
+should only happen after mem_sharing already relinquished all shared pages.
+
+In this patch we flip the order in which relinquish ops are called to avoid
+tripping the assert. Conceptually sharing being torn down makes sense to
+happen before paging is torn down.
+
+Fixes: e7aa55c0aab3 ("x86/p2m: free the paging memory pool preemptively")
+Signed-off-by: Tamas K Lengyel <tamas@tklengyel.com>
+Reviewed-by: Jan Beulich <jbeulich@suse.com>
+master commit: 2869349f0cb3a89dcbf1f1b30371f58df6309312
+master date: 2023-02-23 12:35:48 +0100
+---
+ xen/arch/x86/domain.c | 56 ++++++++++++++++++++++---------------------
+ 1 file changed, 29 insertions(+), 27 deletions(-)
+
+diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
+index 3080cde62b..6eeb248908 100644
+--- a/xen/arch/x86/domain.c
++++ b/xen/arch/x86/domain.c
+@@ -2343,9 +2343,9 @@ int domain_relinquish_resources(struct domain *d)
+ 
+         enum {
+             PROG_iommu_pagetables = 1,
++            PROG_shared,
+             PROG_paging,
+             PROG_vcpu_pagetables,
+-            PROG_shared,
+             PROG_xen,
+             PROG_l4,
+             PROG_l3,
+@@ -2364,6 +2364,34 @@ int domain_relinquish_resources(struct domain *d)
+         if ( ret )
+             return ret;
+ 
++#ifdef CONFIG_MEM_SHARING
++    PROGRESS(shared):
++
++        if ( is_hvm_domain(d) )
++        {
++            /*
++             * If the domain has shared pages, relinquish them allowing
++             * for preemption.
++             */
++            ret = relinquish_shared_pages(d);
++            if ( ret )
++                return ret;
++
++            /*
++             * If the domain is forked, decrement the parent's pause count
++             * and release the domain.
++             */
++            if ( mem_sharing_is_fork(d) )
++            {
++                struct domain *parent = d->parent;
++
++                d->parent = NULL;
++                domain_unpause(parent);
++                put_domain(parent);
++            }
++        }
++#endif
++
+     PROGRESS(paging):
+ 
+         /* Tear down paging-assistance stuff. */
+@@ -2404,32 +2432,6 @@ int domain_relinquish_resources(struct domain *d)
+             d->arch.auto_unmask = 0;
+         }
+ 
+-#ifdef CONFIG_MEM_SHARING
+-    PROGRESS(shared):
+-
+-        if ( is_hvm_domain(d) )
+-        {
+-            /* If the domain has shared pages, relinquish them allowing
+-             * for preemption. */
+-            ret = relinquish_shared_pages(d);
+-            if ( ret )
+-                return ret;
+-
+-            /*
+-             * If the domain is forked, decrement the parent's pause count
+-             * and release the domain.
+-             */
+-            if ( mem_sharing_is_fork(d) )
+-            {
+-                struct domain *parent = d->parent;
+-
+-                d->parent = NULL;
+-                domain_unpause(parent);
+-                put_domain(parent);
+-            }
+-        }
+-#endif
+-
+         spin_lock(&d->page_alloc_lock);
+         page_list_splice(&d->arch.relmem_list, &d->page_list);
+         INIT_PAGE_LIST_HEAD(&d->arch.relmem_list);
+-- 
+2.40.0
+