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Message-Id: <20220628135619.32410-17-imbrenda@linux.ibm.com>
Date: Tue, 28 Jun 2022 15:56:17 +0200
From: Claudio Imbrenda <imbrenda@...ux.ibm.com>
To: kvm@...r.kernel.org
Cc: borntraeger@...ibm.com, frankja@...ux.ibm.com, thuth@...hat.com,
pasic@...ux.ibm.com, david@...hat.com, linux-s390@...r.kernel.org,
linux-kernel@...r.kernel.org, scgl@...ux.ibm.com,
mimu@...ux.ibm.com, nrb@...ux.ibm.com
Subject: [PATCH v12 16/18] KVM: s390: pv: avoid export before import if possible
If the appropriate UV feature bit is set, there is no need to perform
an export before import.
Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
Reviewed-by: Nico Boehr <nrb@...ux.ibm.com>
---
arch/s390/kernel/uv.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 87b176008785..bfc85b0376e4 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -255,6 +255,8 @@ 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)
{
+ if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications))
+ return false;
if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED)
return false;
return atomic_read(&mm->context.protected_count) > 1;
--
2.36.1
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