diff options
Diffstat (limited to '0029-x86-perform-mem_sharing-teardown-before-paging-teard.patch')
| -rw-r--r-- | 0029-x86-perform-mem_sharing-teardown-before-paging-teard.patch | 111 |
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 + |