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authorJuergen Gross <jgross@suse.com>2023-01-09 16:09:22 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-08 19:58:33 +0200
commit13ec5cb4c113d9159b5138d45f588f40ba66ca56 (patch)
treecad8c15ad6f5874680ef0bbbc472af80a48a8716
parent3e90080d56652be6cc9e5355ea65f569bf005fba (diff)
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x86/mm: fix poking_init() for Xen PV guests
commit 26ce6ec364f18d2915923bc05784084e54a5c4cc upstream. Commit 3f4c8211d982 ("x86/mm: Use mm_alloc() in poking_init()") broke the kernel for running as Xen PV guest. It seems as if the new address space is never activated before being used, resulting in Xen rejecting to accept the new CR3 value (the PGD isn't pinned). Fix that by adding the now missing call of paravirt_arch_dup_mmap() to poking_init(). That call was previously done by dup_mm()->dup_mmap() and it is a NOP for all cases but for Xen PV, where it is just doing the pinning of the PGD. Fixes: 3f4c8211d982 ("x86/mm: Use mm_alloc() in poking_init()") Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230109150922.10578-1-jgross@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/mm/init.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 34a08f6a528e..5bb3cc66cccc 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -27,6 +27,7 @@
#include <asm/pti.h>
#include <asm/text-patching.h>
#include <asm/memtype.h>
+#include <asm/paravirt.h>
/*
* We need to define the tracepoints somewhere, and tlb.c
@@ -825,6 +826,9 @@ void __init poking_init(void)
poking_mm = copy_init_mm();
BUG_ON(!poking_mm);
+ /* Xen PV guests need the PGD to be pinned. */
+ paravirt_arch_dup_mmap(NULL, poking_mm);
+
/*
* Randomize the poking address, but make sure that the following page
* will be mapped at the same PMD. We need 2 pages, so find space for 3,