[PATCH] KVM: SEV: drop FOLL_LONGTERM for encrypted region registration

[Pankaj Gupta]

commit 7e066cb9b71a ("KVM: SEV: Use long-term pin when registering encrypted memory regions")
added FOLL_LONGTERM to sev_mem_enc_register_region() so anonymous guest RAM is
migrated out of MIGRATE_CMA/ZONE_MOVABLE before a long term pin. This breaks
virtio-pmem which has file backed (MAP_SHARED) host mapping where GUP rejects
FOLL_WRITE | FOLL_LONGTERM since:

commit 8ac268436e6d ("mm/gup: disallow FOLL_LONGTERM GUP-nonfast writing to file-backed mappings")
commit a6e79df92e4a ("mm/gup: disallow FOLL_LONGTERM GUP-fast writing to file-backed mappings").

Drop FOLL_LONGTERM when registering encrypted memory regions and restore
the previous behavior.

Fixes: 7e066cb9b71a ("KVM: SEV: Use long-term pin when registering encrypted memory regions")
Cc: stable@xxxxxxxxxxxxxxx

Signed-off-by: Pankaj Gupta <pankaj.gupta@xxxxxxx>
---
 arch/x86/kvm/svm/sev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 6c6a6d663e29..c4b53700f69e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2764,7 +2764,7 @@ int sev_mem_enc_register_region(struct kvm *kvm,
 		return -ENOMEM;
 
 	region->pages = sev_pin_memory(kvm, range->addr, range->size, &region->npages,
-				       FOLL_WRITE | FOLL_LONGTERM);
+				       FOLL_WRITE);
 	if (IS_ERR(region->pages)) {
 		ret = PTR_ERR(region->pages);
 		goto e_free;
-- 
2.34.1