public inbox for kvm@vger.kernel.org
 help / color / mirror / Atom feed
From: Janosch Frank <frankja@linux.ibm.com>
To: kvm@vger.kernel.org
Cc: linux-s390@vger.kernel.org, david@redhat.com, thuth@redhat.com
Subject: [kvm-unit-tests PATCH v2 1/3] s390x: Fix initial cr0 load comments
Date: Mon, 11 Nov 2019 10:33:43 -0500	[thread overview]
Message-ID: <20191111153345.22505-2-frankja@linux.ibm.com> (raw)
In-Reply-To: <20191111153345.22505-1-frankja@linux.ibm.com>

We need to load cr0 to have access to all fprs during save and restore
of fprs. Saving conditionally on basis of the CR0 AFP bit would be a
pain.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 s390x/cstart64.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index 8e2b21e..043e34a 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -94,7 +94,7 @@ memsetxc:
 	stmg	%r0, %r15, GEN_LC_SW_INT_GRS
 	/* save cr0 */
 	stctg	%c0, %c0, GEN_LC_SW_INT_CR0
-	/* load initial cr0 again */
+	/* load a cr0 that has the AFP control bit which enables all FPRs */
 	larl	%r1, initial_cr0
 	lctlg	%c0, %c0, 0(%r1)
 	/* save fprs 0-15 + fpc */
@@ -139,7 +139,7 @@ diag308_load_reset:
 	xgr	%r2, %r2
 	br	%r14
 	/* Success path */
-	/* We lost cr0 due to the reset */
+	/* load a cr0 that has the AFP control bit which enables all FPRs */
 0:	larl	%r1, initial_cr0
 	lctlg	%c0, %c0, 0(%r1)
 	RESTORE_REGS
-- 
2.20.1


  reply	other threads:[~2019-11-11 15:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-11 15:33 [kvm-unit-tests PATCH v2 0/3] s390x: Improve architectural compliance for diag308 Janosch Frank
2019-11-11 15:33 ` Janosch Frank [this message]
2019-11-12  9:25   ` [kvm-unit-tests PATCH v2 1/3] s390x: Fix initial cr0 load comments Thomas Huth
2019-11-11 15:33 ` [kvm-unit-tests PATCH v2 2/3] s390x: Add CR save area Janosch Frank
2019-11-11 17:22   ` David Hildenbrand
2019-11-12  9:41   ` Thomas Huth
2019-11-11 15:33 ` [kvm-unit-tests PATCH v2 3/3] s390x: Load reset psw on diag308 reset Janosch Frank
2019-11-12  9:53   ` Thomas Huth
2019-11-12 12:09   ` David Hildenbrand
2019-11-12 13:42     ` Janosch Frank
2019-11-12 16:17       ` Thomas Huth
2019-11-13 10:04         ` Janosch Frank
2019-11-13 10:31           ` Thomas Huth
2019-11-13 11:24             ` [kvm-unit-tests PATCH v4] " Janosch Frank
2019-11-13 18:06               ` David Hildenbrand
2019-11-14  7:24                 ` Janosch Frank
2019-11-12 13:45     ` [kvm-unit-tests PATCH v3] " Janosch Frank
2019-11-12 12:10 ` [kvm-unit-tests PATCH v2 0/3] s390x: Improve architectural compliance for diag308 David Hildenbrand

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191111153345.22505-2-frankja@linux.ibm.com \
    --to=frankja@linux.ibm.com \
    --cc=david@redhat.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=thuth@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox