From: Heiko Carstens <hca@linux.ibm.com>
To: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Thomas Huth <thuth@redhat.com>, Farhan Ali <alifm@linux.ibm.com>,
qemu-devel@nongnu.org, alex.williamson@redhat.com,
stefanha@redhat.com, mjrosato@linux.ibm.com, philmd@linaro.org,
kwolf@redhat.com, hreitz@redhat.com, fam@euphon.net
Subject: Re: [PATCH v5 1/3] util: Add functions for s390x mmio read/write
Date: Fri, 25 Apr 2025 16:09:29 +0200 [thread overview]
Message-ID: <20250425140929.7180Fdb-hca@linux.ibm.com> (raw)
In-Reply-To: <aae585ad4d9884e204ff1f153f4d1be5453b284a.camel@linux.ibm.com>
On Fri, Apr 25, 2025 at 12:29:35PM +0200, Niklas Schnelle wrote:
> On Fri, 2025-04-25 at 11:00 +0200, Thomas Huth wrote:
> > On 17/04/2025 19.37, Farhan Ali wrote:
> > > + asm volatile(
> > > + /* pcilgi */
> > > + ".insn rre,0xb9d60000,%[val],%[ioaddr_len]\n"
> > > + "ipm %[cc]\n"
> > > + "srl %[cc],28\n"
> > > + : [cc] "=d"(cc), [val] "=d"(val),
> > > + [ioaddr_len] "+&d"(ioaddr_len.pair) :: "cc");
> >
> > Do we need the "&" modifier here? ... at least the kernel does not seem to
> > use it ...
>
> From my understanding it's not strictly needed, but I also used it in
> the rdma-core user-space code where I had pointed Farhan. I looked at
It is not needed, since all inputs are consumed before to any output
is written to.
> > > + asm volatile (
> > > + /* pcistgi */
> > > + ".insn rre,0xb9d40000,%[val],%[ioaddr_len]\n"
> > > + : [ioaddr_len] "+&d" (ioaddr_len.pair)
> >
> > dito
Same here, it is not needed.
next prev parent reply other threads:[~2025-04-25 14:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-17 17:37 [PATCH v5 0/3] Enable QEMU NVMe userspace driver on s390x Farhan Ali
2025-04-17 17:37 ` [PATCH v5 1/3] util: Add functions for s390x mmio read/write Farhan Ali
2025-04-25 9:00 ` Thomas Huth
2025-04-25 10:29 ` Niklas Schnelle
2025-04-25 14:09 ` Heiko Carstens [this message]
2025-04-30 16:42 ` Farhan Ali
2025-04-17 17:38 ` [PATCH v5 2/3] include: Add a header to define host PCI MMIO functions Farhan Ali
2025-04-22 14:45 ` Stefan Hajnoczi
2025-04-25 9:17 ` Thomas Huth
2025-04-30 16:47 ` Farhan Ali
2025-04-30 17:52 ` Thomas Huth
2025-04-30 18:32 ` Farhan Ali
2025-04-30 18:38 ` Thomas Huth
2025-04-17 17:38 ` [PATCH v5 3/3] block/nvme: Use host PCI MMIO API Farhan Ali
2025-04-25 9:22 ` Thomas Huth
2025-04-24 16:24 ` [PATCH v5 0/3] Enable QEMU NVMe userspace driver on s390x Farhan Ali
2025-04-25 9:24 ` Thomas Huth
2025-04-25 9:59 ` Philippe Mathieu-Daudé
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