[PATCH v2 13/13] KVM: s390: pv: add support for UV feature bits

Claudio Imbrenda
2021-07-28T14:27:02Z

Add support for Ultravisor feature bits, and take advantage of the
functionality advertised to speed up the lazy destroy mechanism.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
arch/s390/kernel/uv.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index f0af49b09a91..6ec3d7338ec8 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -290,7 +290,8 @@ static int make_secure_pte(pte_t *ptep, unsigned long addr,

static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm)
{
- return uvcb->cmd != UVC_CMD_UNPIN_PAGE_SHARED &&
+ return !test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) &&
+ uvcb->cmd != UVC_CMD_UNPIN_PAGE_SHARED &&
atomic_read(&mm->context.is_protected) > 1;
}

--
2.31.1