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Re: [qemu-s390x] [Qemu-devel] [PATCH v1 0/5][RFC] Refactoring of AIS sup

From: Pierre Morel
Subject: Re: [qemu-s390x] [Qemu-devel] [PATCH v1 0/5][RFC] Refactoring of AIS support
Date: Mon, 30 Oct 2017 18:38:34 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0

On 30/10/2017 18:08, Christian Borntraeger wrote:

On 10/30/2017 05:59 PM, Cornelia Huck wrote:
On Mon, 30 Oct 2017 14:48:23 +0100
Christian Borntraeger <address@hidden> wrote:

FWIW, I am testing a guest patch that enables zPCI without AIS. Its as simple as

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 7b30af5..9b24836 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -953,7 +953,7 @@ static int __init pci_base_init(void)
         if (!s390_pci_probe)
                 return 0;
- if (!test_facility(69) || !test_facility(71) || !test_facility(72))
+       if (!test_facility(69) || !test_facility(71))
                 return 0;
rc = zpci_debug_init();
diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
index ea34086..61f8c82 100644
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -7,6 +7,7 @@
  #include <linux/export.h>
  #include <linux/errno.h>
  #include <linux/delay.h>
+#include <asm/facility.h>
  #include <asm/pci_insn.h>
  #include <asm/pci_debug.h>
  #include <asm/processor.h>
@@ -93,6 +94,8 @@ int zpci_refresh_trans(u64 fn, u64 addr, u64 range)
  /* Set Interruption Controls */
  void zpci_set_irq_ctrl(u16 ctl, char *unused, u8 isc)
+       if (!test_facility(72))
+               return;
         asm volatile (
                 "       .insn   rsy,0xeb00000000d1,%[ctl],%[isc],%[u]\n"
                 : : [ctl] "d" (ctl), [isc] "d" (isc << 27), [u] "Q" (*unused));

Sounds good. Presumably this makes the adapter interrupt handling work
as for virtio (and qdio)? Is there any ais-less pci hardware out in the

ais is z specific, not PCI specific. So PCI cards should not care as far as I 
can tell.

I bet Conny meant PCI hardware globaly, including zPCI adapters.
I bet none but I will better ask Sebastian or Gerald if they know.

Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany

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