From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:23536 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731467AbgAIRFw (ORCPT ); Thu, 9 Jan 2020 12:05:52 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 009H2aSp130071 for ; Thu, 9 Jan 2020 12:05:50 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2xe5rxe6nr-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 09 Jan 2020 12:05:50 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 9 Jan 2020 17:05:48 -0000 Subject: Re: [kvm-unit-tests PATCH v6 3/4] s390x: lib: add SPX and STPX instruction wrapper References: <20200109161625.154894-1-imbrenda@linux.ibm.com> <20200109161625.154894-4-imbrenda@linux.ibm.com> <5c6f563e-3d09-5274-b050-a64122097e9b@redhat.com> <20200109175027.362d8440@p-imbrenda> <3dc2cf13-4829-53cd-a0a6-734fdddeb0ac@redhat.com> From: Janosch Frank Date: Thu, 9 Jan 2020 18:05:42 +0100 MIME-Version: 1.0 In-Reply-To: <3dc2cf13-4829-53cd-a0a6-734fdddeb0ac@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="zr67qUUwMF4HbjZpi0SDrVLCAGEKlUtFu" Message-Id: <920208a7-562f-9a54-11cc-6ece021469ec@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Thomas Huth , Claudio Imbrenda Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, david@redhat.com, borntraeger@de.ibm.com This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --zr67qUUwMF4HbjZpi0SDrVLCAGEKlUtFu Content-Type: multipart/mixed; boundary="qEuZ6r7k8Bu8J0ttgt5ZJgwqJGKX7UwDd" --qEuZ6r7k8Bu8J0ttgt5ZJgwqJGKX7UwDd Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 1/9/20 5:58 PM, Thomas Huth wrote: > On 09/01/2020 17.50, Claudio Imbrenda wrote: >> On Thu, 9 Jan 2020 17:43:55 +0100 >> Thomas Huth wrote: >> >>> On 09/01/2020 17.16, Claudio Imbrenda wrote: >>>> Add a wrapper for the SET PREFIX and STORE PREFIX instructions, and >>>> use it instead of using inline assembly everywhere. >>>> >>>> Signed-off-by: Claudio Imbrenda >>>> --- >>>> lib/s390x/asm/arch_def.h | 10 ++++++++++ >>>> s390x/intercept.c | 33 +++++++++++++-------------------- >>>> 2 files changed, 23 insertions(+), 20 deletions(-) >>>> >>>> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h >>>> index 1a5e3c6..465fe0f 100644 >>>> --- a/lib/s390x/asm/arch_def.h >>>> +++ b/lib/s390x/asm/arch_def.h >>>> @@ -284,4 +284,14 @@ static inline int servc(uint32_t command, >>>> unsigned long sccb) return cc; >>>> } >>>> =20 >>>> +static inline void spx(uint32_t *new_prefix) =20 >>> >>> Looking at this a second time ... why is new_prefix a pointer? A >>> normal value should be sufficient here, shouldn't it? >> >> no. if you look at the code in the same patch, intercept.c at some >> points needs to pass "wrong" pointers to spx and stpx in order to test= >> them, so this needs to be a pointer >> >> the instructions themselves expect pointers (base register + offset) >=20 > Ah, you're right, that "Q" constraint always confuses me... I guess you= > could do it without pointers when using the "r" constraint, but it's > likely better to do it the same way as stpx, so your patch should be fi= ne. Honestly, I'd rather have stpx return a u32 than passing a ptr. That's how the kernel does it and is in-line with epswe/lpswe and sctlg/lctlg which are already in the library. Also, if possible names like set_prefix and store_prefix (or better get_prefix) prefix would make it much more readable. >=20 >>>> +{ >>>> + asm volatile("spx %0" : : "Q" (*new_prefix) : "memory"); >>>> +} >>>> + >>>> +static inline void stpx(uint32_t *current_prefix) >>>> +{ >>>> + asm volatile("stpx %0" : "=3DQ" (*current_prefix)); >>>> +} >>>> + =20 >=20 > Reviewed-by: Thomas Huth >=20 --qEuZ6r7k8Bu8J0ttgt5ZJgwqJGKX7UwDd-- --zr67qUUwMF4HbjZpi0SDrVLCAGEKlUtFu Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEwGNS88vfc9+v45Yq41TmuOI4ufgFAl4XXWYACgkQ41TmuOI4 ufjBWhAA0BLaCmqO5xIMN106t3qhouiw4IyXNW9CicOtalmcGSDQtU6JJufArLko 3XT/wxE3OWEzPPSmQloRbiJP72NZhxOtaK8+rbl3gMFOTC5e2eKwvGLv7V3ryn2U UI8PtCzXhsDIWNee7YoaLl857/7bbT9kiYsQIOUZdxBKAgsSFXK1H0zWRRCZ5xiL km5a9pT6BEC587UBViwgO/VKClLttCZXvBEeNkWkg2sb2R9/2MK9G5f68cn197DJ lc7Lc00RdmT2bpucfl0RxS0TUl45L8ymReBFgYXiV85pmS9SqvXtQFF/fEHZPrGJ FAJoupLpSPsqk2ipq0YMYIfZsalQ/8FF4dyp/xcZ/cIlgtglKwq0QRLAbbvpsGQr coF4klQWtn15n1tJ7QlxoTOSkjXTF8OSnsdHcFV6YlChDy0tax8jXxrHSGOIi6AS d1VgsyezeEjk9Oel8c80dcXA6Rx5sQB6twABLv8lXcwAuhW+CG7hmRv8GsMMtjxU 95CPut4po955lpsb+v79nJRuMnvtFT48tk1DvS7l8XHpeykHEWLnGUCcAZr2G1R5 +aeR0/MVdW7+nsJkyuxG5O7Ue6bLWPHipe2TWFSrFDyRawbO7qZJuXi7ctqzwXLy I6miNvZDhkDcKZLdMs+UYa26vBU/AJFYH40jPhQ0Y6ynnhQ3iGA= =fB/S -----END PGP SIGNATURE----- --zr67qUUwMF4HbjZpi0SDrVLCAGEKlUtFu--