From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f4Nso-0007Ne-6F for qemu-devel@nongnu.org; Fri, 06 Apr 2018 05:42:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f4Nsk-0008PP-4W for qemu-devel@nongnu.org; Fri, 06 Apr 2018 05:42:10 -0400 Date: Fri, 6 Apr 2018 11:42:02 +0200 From: Cornelia Huck Message-ID: <20180406114202.2cf34236.cohuck@redhat.com> In-Reply-To: <8080442a-bd0b-6231-630c-39b48f910c7a@redhat.com> References: <1522940844-12336-1-git-send-email-mihajlov@linux.vnet.ibm.com> <1522940844-12336-4-git-send-email-mihajlov@linux.vnet.ibm.com> <8080442a-bd0b-6231-630c-39b48f910c7a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] s390: Do not pass inofficial IPL type to the guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth Cc: Viktor Mihajlovski , borntraeger@de.ibm.com, agraf@suse.de, rth@twiddle.net, david@redhat.com, qemu-devel@nongnu.org, qemu-s390x@nongnu.org On Fri, 6 Apr 2018 11:28:31 +0200 Thomas Huth wrote: > On 05.04.2018 17:07, Viktor Mihajlovski wrote: > > IPL over a virtio-scsi device requires special handling not > > available in the real architecture. For this purpose the IPL > > type 0xFF has been chosen as means of communication between > > QEMU and the pc-bios. However, a guest OS could be confused > > by seeing an unknown IPL type. > > > > This change sets the IPL parameter type to 0x02 (CCW) to prevent > > this. Pre-existing Linux has looked up the IPL parameters only in > > the case of FCP IPL. This means that the behavior should stay > > the same even if Linux checks for the IPL type unconditionally. > > > > Signed-off-by: Viktor Mihajlovski > > --- > > pc-bios/s390-ccw/bootmap.c | 7 +++++++ > > pc-bios/s390-ccw/iplb.h | 15 +++++++++++++-- > > 2 files changed, 20 insertions(+), 2 deletions(-) > > > > diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c > > index fc2a9fe..9287b7a 100644 > > --- a/pc-bios/s390-ccw/bootmap.c > > +++ b/pc-bios/s390-ccw/bootmap.c > > @@ -70,6 +70,13 @@ static void jump_to_IPL_code(uint64_t address) > > { > > /* store the subsystem information _after_ the bootmap was loaded */ > > write_subsystem_identification(); > > + > > + /* prevent unknown IPL types in the guest */ > > + if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) { > > + iplb.pbt = S390_IPL_TYPE_CCW; > > + set_iplb(&iplb); > > + } > > + > > /* > > * The IPL PSW is at address 0. We also must not overwrite the > > * content of non-BIOS memory after we loaded the guest, so we > > diff --git a/pc-bios/s390-ccw/iplb.h b/pc-bios/s390-ccw/iplb.h > > index 7dfce4f..5357a36 100644 > > --- a/pc-bios/s390-ccw/iplb.h > > +++ b/pc-bios/s390-ccw/iplb.h > > @@ -97,16 +97,27 @@ extern QemuIplParameters qipl; > > #define S390_IPL_TYPE_CCW 0x02 > > #define S390_IPL_TYPE_QEMU_SCSI 0xff > > > > -static inline bool store_iplb(IplParameterBlock *iplb) > > +static inline bool manage_iplb(IplParameterBlock *iplb, bool store) > > { > > register unsigned long addr asm("0") = (unsigned long) iplb; > > register unsigned long rc asm("1") = 0; > > > > asm volatile ("diag %0,%2,0x308\n" > > : "+d" (addr), "+d" (rc) > > - : "d" (6) > > + : "d" (store ? 6 : 5) > > : "memory", "cc"); > > I can't find a proper public specification for diag 308, so no clue how > to review this properly. Christian, could you please have a look? It does match the diag 308 store/load implementation in target/s390x/diag.c... but a pointer to an official spec (if public) would still be appreciated :)