From 882213990d32fd224340a4533f6318dd152be4b2 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 24 Feb 2021 16:03:08 +0100 Subject: xen: fix p2m size in dom0 for disabled memory hotplug case MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory") foreign mappings are using guest physical addresses allocated via ZONE_DEVICE functionality. This will result in problems for the case of no balloon memory hotplug being configured, as the p2m list will only cover the initial memory size of the domain. Any ZONE_DEVICE allocated address will be outside the p2m range and thus a mapping can't be established with that memory address. Fix that by extending the p2m size for that case. At the same time add a check for a to be created mapping to be within the p2m limits in order to detect errors early. While changing a comment, remove some 32-bit leftovers. This is XSA-369. Fixes: 9e2369c06c8a18 ("xen: add helpers to allocate unpopulated memory") Cc: # 5.9 Reported-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross Reviewed-by: Jan Beulich Signed-off-by: Juergen Gross --- arch/x86/xen/p2m.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'arch/x86/xen/p2m.c') diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 9545b8df5315..a3cc33091f46 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -416,6 +416,9 @@ void __init xen_vmalloc_p2m_tree(void) xen_p2m_last_pfn = xen_max_p2m_pfn; p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE; + if (!p2m_limit && IS_ENABLED(CONFIG_XEN_UNPOPULATED_ALLOC)) + p2m_limit = xen_start_info->nr_pages * XEN_EXTRA_MEM_RATIO; + vm.flags = VM_ALLOC; vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit), PMD_SIZE * PMDS_PER_MID_PAGE); @@ -652,10 +655,9 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) pte_t *ptep; unsigned int level; - if (unlikely(pfn >= xen_p2m_size)) { - BUG_ON(mfn != INVALID_P2M_ENTRY); - return true; - } + /* Only invalid entries allowed above the highest p2m covered frame. */ + if (unlikely(pfn >= xen_p2m_size)) + return mfn == INVALID_P2M_ENTRY; /* * The interface requires atomic updates on p2m elements. -- cgit v1.2.3