From 9a58b352e9e8a8c897acf6aae5cacd7d481965f9 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 30 Sep 2021 14:37:19 +0200 Subject: [PATCH] xen/x86: restrict PV Dom0 identity mapping When moving away RAM pages, there having been a mapping of those is not a proper indication that instead MMIO should be mapped there. At the point in time this effectively covers the low megabyte only. Mapping of that is, however, the job of init_mem_mapping(). Comparing the two one can also spot that we've been wrongly (or at least inconsistently) using PAGE_KERNEL_IO here. Simply zap any such mappings instead. Signed-off-by: Jan Beulich Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/038b8c02-3621-d66a-63ae-982ccf67ae88@suse.com Signed-off-by: Boris Ostrovsky --- arch/x86/xen/setup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index c1eba7e..b5a6c20 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -425,13 +425,13 @@ static unsigned long __init xen_set_identity_and_remap_chunk( } /* - * If the PFNs are currently mapped, the VA mapping also needs - * to be updated to be 1:1. + * If the PFNs are currently mapped, their VA mappings need to be + * zapped. */ for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) (void)HYPERVISOR_update_va_mapping( (unsigned long)__va(pfn << PAGE_SHIFT), - mfn_pte(pfn, PAGE_KERNEL_IO), 0); + native_make_pte(0), 0); return remap_pfn; } -- 2.7.4