[Qemu-devel] [PATCH] s390x: always provide pci support

[Qemu-devel] [PATCH] s390x: always provide pci support

[Cornelia Huck]

We tried to make pci support optional on s390x in the past;
unfortunately, we still require the s390 phb to be created
unconditionally due to backwards compatibility issues.

Instead of sinking more effort into this (including compat
handling for older machines etc.) for non-obvious gains, let's
just make CONFIG_PCI something that is always set on s390x.

Note that you can still fence off pci for the _guest_ if you
provide a cpu model without the zpci feature.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
Follow-up patch to the discussion around "hw/s390x: Fix the function
arguments in the pci stub file". I've done a quick sanity test with
tcg only so far.
---
 hw/s390x/Makefile.objs      |  3 +-
 hw/s390x/s390-pci-stub.c    | 77 -------------------------------------
 hw/s390x/s390-virtio-ccw.c  |  4 --
 target/s390x/cpu_models.c   |  5 ---
 target/s390x/gen-features.c |  1 -
 target/s390x/kvm.c          |  4 +-
 6 files changed, 2 insertions(+), 92 deletions(-)
 delete mode 100644 hw/s390x/s390-pci-stub.c

diff --git a/hw/s390x/Makefile.objs b/hw/s390x/Makefile.objs
index a18c4719137e..bfd5326d7c3d 100644
--- a/hw/s390x/Makefile.objs
+++ b/hw/s390x/Makefile.objs
@@ -21,8 +21,7 @@ obj-$(call land,$(CONFIG_VIRTIO_9P),$(CONFIG_VIRTFS)) += virtio-ccw-9p.o
 obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-ccw.o
 obj-y += css-bridge.o
 obj-y += ccw-device.o
-obj-$(CONFIG_PCI) += s390-pci-bus.o s390-pci-inst.o
-obj-$(call lnot,$(CONFIG_PCI)) += s390-pci-stub.o
+obj-y += s390-pci-bus.o s390-pci-inst.o
 obj-y += s390-skeys.o
 obj-y += s390-stattrib.o
 obj-y += tod.o
diff --git a/hw/s390x/s390-pci-stub.c b/hw/s390x/s390-pci-stub.c
deleted file mode 100644
index ad4c5a77198f..000000000000
--- a/hw/s390x/s390-pci-stub.c
+++ /dev/null
@@ -1,77 +0,0 @@
-/* stubs for non-pci builds */
-
-#include "qemu/osdep.h"
-#include "qemu-common.h"
-#include "cpu.h"
-#include "s390-pci-inst.h"
-#include "s390-pci-bus.h"
-
-/* target/s390x/ioinst.c */
-int pci_chsc_sei_nt2_get_event(void *res)
-{
-    return 1;
-}
-
-int pci_chsc_sei_nt2_have_event(void)
-{
-    return 0;
-}
-
-/* hw/s390x/sclp.c */
-void s390_pci_sclp_configure(SCCB *sccb)
-{
-    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
-}
-
-void s390_pci_sclp_deconfigure(SCCB *sccb)
-{
-    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
-}
-
-/* target/s390x/kvm.c */
-int clp_service_call(S390CPU *cpu, uint8_t r2)
-{
-    return -1;
-}
-
-int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
-{
-    return -1;
-}
-
-int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
-{
-    return -1;
-}
-
-int stpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
-{
-    return -1;
-}
-
-int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
-{
-    return -1;
-}
-
-int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
-                        uint8_t ar)
-{
-    return -1;
-}
-
-int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
-{
-    return -1;
-}
-
-S390pciState *s390_get_phb(void)
-{
-    return NULL;
-}
-
-S390PCIBusDevice *s390_pci_find_dev_by_target(S390pciState *s,
-                                              const char *target)
-{
-    return NULL;
-}
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 811fdf913dd6..3fb5c88af9cc 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -272,10 +272,6 @@ static void ccw_init(MachineState *machine)
                       machine->initrd_filename, "s390-ccw.img",
                       "s390-netboot.img", true);
 
-    /*
-     * We cannot easily make the pci host bridge conditional as older QEMUs
-     * always created it. Doing so would break migration across QEMU versions.
-     */
     dev = qdev_create(NULL, TYPE_S390_PCI_HOST_BRIDGE);
     object_property_add_child(qdev_get_machine(), TYPE_S390_PCI_HOST_BRIDGE,
                               OBJECT(dev), NULL);
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 7c253ff308c5..249011fd62f5 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -1314,11 +1314,6 @@ static void register_types(void)
 
     /* init all bitmaps from gnerated data initially */
     s390_init_feat_bitmap(qemu_max_cpu_feat_init, qemu_max_cpu_feat);
-#ifndef CONFIG_USER_ONLY
-    if (!pci_available) {
-        clear_bit(S390_FEAT_ZPCI, qemu_max_cpu_feat);
-    }
-#endif
     for (i = 0; i < ARRAY_SIZE(s390_cpu_defs); i++) {
         s390_init_feat_bitmap(s390_cpu_defs[i].base_init,
                               s390_cpu_defs[i].base_feat);
diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
index 70015eaaf5df..b0e9b271e228 100644
--- a/target/s390x/gen-features.c
+++ b/target/s390x/gen-features.c
@@ -598,7 +598,6 @@ static uint16_t qemu_MAX[] = {
     S390_FEAT_STFLE_53,
     /* generates a dependency warning, leave it out for now */
     S390_FEAT_MSA_EXT_5,
-    /* only with CONFIG_PCI */
     S390_FEAT_ZPCI,
 };
 
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 9ff80c8461d0..15fdc168e1c5 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2278,9 +2278,7 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
     }
 
     /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
-    if (pci_available) {
-        set_bit(S390_FEAT_ZPCI, model->features);
-    }
+    set_bit(S390_FEAT_ZPCI, model->features);
     set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
 
     if (s390_known_cpu_type(cpu_type)) {
-- 
2.17.2

Re: [Qemu-devel] [qemu-s390x] [PATCH] s390x: always provide pci support

[Thomas Huth]

On 2019-02-11 12:32, Cornelia Huck wrote:
> We tried to make pci support optional on s390x in the past;
> unfortunately, we still require the s390 phb to be created
> unconditionally due to backwards compatibility issues.
> 
> Instead of sinking more effort into this (including compat
> handling for older machines etc.) for non-obvious gains, let's
> just make CONFIG_PCI something that is always set on s390x.
> 
> Note that you can still fence off pci for the _guest_ if you
> provide a cpu model without the zpci feature.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> Follow-up patch to the discussion around "hw/s390x: Fix the function
> arguments in the pci stub file". I've done a quick sanity test with
> tcg only so far.
> ---
>  hw/s390x/Makefile.objs      |  3 +-
>  hw/s390x/s390-pci-stub.c    | 77 -------------------------------------
>  hw/s390x/s390-virtio-ccw.c  |  4 --
>  target/s390x/cpu_models.c   |  5 ---
>  target/s390x/gen-features.c |  1 -
>  target/s390x/kvm.c          |  4 +-
>  6 files changed, 2 insertions(+), 92 deletions(-)
>  delete mode 100644 hw/s390x/s390-pci-stub.c

Reviewed-by: Thomas Huth <thuth@redhat.com>

Re: [Qemu-devel] [PATCH] s390x: always provide pci support

[David Hildenbrand]

On 11.02.19 12:32, Cornelia Huck wrote:
> We tried to make pci support optional on s390x in the past;
> unfortunately, we still require the s390 phb to be created
> unconditionally due to backwards compatibility issues.
> 
> Instead of sinking more effort into this (including compat
> handling for older machines etc.) for non-obvious gains, let's
> just make CONFIG_PCI something that is always set on s390x.
> 
> Note that you can still fence off pci for the _guest_ if you
> provide a cpu model without the zpci feature.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> Follow-up patch to the discussion around "hw/s390x: Fix the function
> arguments in the pci stub file". I've done a quick sanity test with
> tcg only so far.
> ---
>  hw/s390x/Makefile.objs      |  3 +-
>  hw/s390x/s390-pci-stub.c    | 77 -------------------------------------
>  hw/s390x/s390-virtio-ccw.c  |  4 --
>  target/s390x/cpu_models.c   |  5 ---
>  target/s390x/gen-features.c |  1 -
>  target/s390x/kvm.c          |  4 +-
>  6 files changed, 2 insertions(+), 92 deletions(-)
>  delete mode 100644 hw/s390x/s390-pci-stub.c
> 
> diff --git a/hw/s390x/Makefile.objs b/hw/s390x/Makefile.objs
> index a18c4719137e..bfd5326d7c3d 100644
> --- a/hw/s390x/Makefile.objs
> +++ b/hw/s390x/Makefile.objs
> @@ -21,8 +21,7 @@ obj-$(call land,$(CONFIG_VIRTIO_9P),$(CONFIG_VIRTFS)) += virtio-ccw-9p.o
>  obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-ccw.o
>  obj-y += css-bridge.o
>  obj-y += ccw-device.o
> -obj-$(CONFIG_PCI) += s390-pci-bus.o s390-pci-inst.o
> -obj-$(call lnot,$(CONFIG_PCI)) += s390-pci-stub.o
> +obj-y += s390-pci-bus.o s390-pci-inst.o
>  obj-y += s390-skeys.o
>  obj-y += s390-stattrib.o
>  obj-y += tod.o
> diff --git a/hw/s390x/s390-pci-stub.c b/hw/s390x/s390-pci-stub.c
> deleted file mode 100644
> index ad4c5a77198f..000000000000
> --- a/hw/s390x/s390-pci-stub.c
> +++ /dev/null
> @@ -1,77 +0,0 @@
> -/* stubs for non-pci builds */
> -
> -#include "qemu/osdep.h"
> -#include "qemu-common.h"
> -#include "cpu.h"
> -#include "s390-pci-inst.h"
> -#include "s390-pci-bus.h"
> -
> -/* target/s390x/ioinst.c */
> -int pci_chsc_sei_nt2_get_event(void *res)
> -{
> -    return 1;
> -}
> -
> -int pci_chsc_sei_nt2_have_event(void)
> -{
> -    return 0;
> -}
> -
> -/* hw/s390x/sclp.c */
> -void s390_pci_sclp_configure(SCCB *sccb)
> -{
> -    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
> -}
> -
> -void s390_pci_sclp_deconfigure(SCCB *sccb)
> -{
> -    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
> -}
> -
> -/* target/s390x/kvm.c */
> -int clp_service_call(S390CPU *cpu, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int stpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
> -                        uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -S390pciState *s390_get_phb(void)
> -{
> -    return NULL;
> -}
> -
> -S390PCIBusDevice *s390_pci_find_dev_by_target(S390pciState *s,
> -                                              const char *target)
> -{
> -    return NULL;
> -}
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 811fdf913dd6..3fb5c88af9cc 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -272,10 +272,6 @@ static void ccw_init(MachineState *machine)
>                        machine->initrd_filename, "s390-ccw.img",
>                        "s390-netboot.img", true);
>  
> -    /*
> -     * We cannot easily make the pci host bridge conditional as older QEMUs
> -     * always created it. Doing so would break migration across QEMU versions.
> -     */
>      dev = qdev_create(NULL, TYPE_S390_PCI_HOST_BRIDGE);
>      object_property_add_child(qdev_get_machine(), TYPE_S390_PCI_HOST_BRIDGE,
>                                OBJECT(dev), NULL);
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index 7c253ff308c5..249011fd62f5 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -1314,11 +1314,6 @@ static void register_types(void)
>  
>      /* init all bitmaps from gnerated data initially */
>      s390_init_feat_bitmap(qemu_max_cpu_feat_init, qemu_max_cpu_feat);
> -#ifndef CONFIG_USER_ONLY
> -    if (!pci_available) {
> -        clear_bit(S390_FEAT_ZPCI, qemu_max_cpu_feat);
> -    }
> -#endif
>      for (i = 0; i < ARRAY_SIZE(s390_cpu_defs); i++) {
>          s390_init_feat_bitmap(s390_cpu_defs[i].base_init,
>                                s390_cpu_defs[i].base_feat);
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 70015eaaf5df..b0e9b271e228 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -598,7 +598,6 @@ static uint16_t qemu_MAX[] = {
>      S390_FEAT_STFLE_53,
>      /* generates a dependency warning, leave it out for now */
>      S390_FEAT_MSA_EXT_5,
> -    /* only with CONFIG_PCI */
>      S390_FEAT_ZPCI,
>  };
>  
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index 9ff80c8461d0..15fdc168e1c5 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -2278,9 +2278,7 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
>      }
>  
>      /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
> -    if (pci_available) {
> -        set_bit(S390_FEAT_ZPCI, model->features);
> -    }
> +    set_bit(S390_FEAT_ZPCI, model->features);
>      set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
>  
>      if (s390_known_cpu_type(cpu_type)) {
> 

Reviewed-by: David Hildenbrand <david@redhat.com>

I'll send a patch that moves zPCI into the default qemu model as I'll be
touching the qemu cpu model either way.

-- 

Thanks,

David / dhildenb

Re: [Qemu-devel] [PATCH] s390x: always provide pci support

[Christian Borntraeger]

On 11.02.2019 12:32, Cornelia Huck wrote:
> We tried to make pci support optional on s390x in the past;
> unfortunately, we still require the s390 phb to be created
> unconditionally due to backwards compatibility issues.
> 
> Instead of sinking more effort into this (including compat
> handling for older machines etc.) for non-obvious gains, let's
> just make CONFIG_PCI something that is always set on s390x.
> 
> Note that you can still fence off pci for the _guest_ if you
> provide a cpu model without the zpci feature.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

The previous attempts of making it configurable caused more  pain than
benefit.
> ---
> Follow-up patch to the discussion around "hw/s390x: Fix the function
> arguments in the pci stub file". I've done a quick sanity test with
> tcg only so far.
> ---
>  hw/s390x/Makefile.objs      |  3 +-
>  hw/s390x/s390-pci-stub.c    | 77 -------------------------------------
>  hw/s390x/s390-virtio-ccw.c  |  4 --
>  target/s390x/cpu_models.c   |  5 ---
>  target/s390x/gen-features.c |  1 -
>  target/s390x/kvm.c          |  4 +-
>  6 files changed, 2 insertions(+), 92 deletions(-)
>  delete mode 100644 hw/s390x/s390-pci-stub.c
> 
> diff --git a/hw/s390x/Makefile.objs b/hw/s390x/Makefile.objs
> index a18c4719137e..bfd5326d7c3d 100644
> --- a/hw/s390x/Makefile.objs
> +++ b/hw/s390x/Makefile.objs
> @@ -21,8 +21,7 @@ obj-$(call land,$(CONFIG_VIRTIO_9P),$(CONFIG_VIRTFS)) += virtio-ccw-9p.o
>  obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-ccw.o
>  obj-y += css-bridge.o
>  obj-y += ccw-device.o
> -obj-$(CONFIG_PCI) += s390-pci-bus.o s390-pci-inst.o
> -obj-$(call lnot,$(CONFIG_PCI)) += s390-pci-stub.o
> +obj-y += s390-pci-bus.o s390-pci-inst.o
>  obj-y += s390-skeys.o
>  obj-y += s390-stattrib.o
>  obj-y += tod.o
> diff --git a/hw/s390x/s390-pci-stub.c b/hw/s390x/s390-pci-stub.c
> deleted file mode 100644
> index ad4c5a77198f..000000000000
> --- a/hw/s390x/s390-pci-stub.c
> +++ /dev/null
> @@ -1,77 +0,0 @@
> -/* stubs for non-pci builds */
> -
> -#include "qemu/osdep.h"
> -#include "qemu-common.h"
> -#include "cpu.h"
> -#include "s390-pci-inst.h"
> -#include "s390-pci-bus.h"
> -
> -/* target/s390x/ioinst.c */
> -int pci_chsc_sei_nt2_get_event(void *res)
> -{
> -    return 1;
> -}
> -
> -int pci_chsc_sei_nt2_have_event(void)
> -{
> -    return 0;
> -}
> -
> -/* hw/s390x/sclp.c */
> -void s390_pci_sclp_configure(SCCB *sccb)
> -{
> -    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
> -}
> -
> -void s390_pci_sclp_deconfigure(SCCB *sccb)
> -{
> -    sccb->h.response_code = cpu_to_be16(SCLP_RC_ADAPTER_TYPE_NOT_RECOGNIZED);
> -}
> -
> -/* target/s390x/kvm.c */
> -int clp_service_call(S390CPU *cpu, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcilg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcistg_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int stpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
> -{
> -    return -1;
> -}
> -
> -int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
> -                        uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar)
> -{
> -    return -1;
> -}
> -
> -S390pciState *s390_get_phb(void)
> -{
> -    return NULL;
> -}
> -
> -S390PCIBusDevice *s390_pci_find_dev_by_target(S390pciState *s,
> -                                              const char *target)
> -{
> -    return NULL;
> -}
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index 811fdf913dd6..3fb5c88af9cc 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -272,10 +272,6 @@ static void ccw_init(MachineState *machine)
>                        machine->initrd_filename, "s390-ccw.img",
>                        "s390-netboot.img", true);
>  
> -    /*
> -     * We cannot easily make the pci host bridge conditional as older QEMUs
> -     * always created it. Doing so would break migration across QEMU versions.
> -     */
>      dev = qdev_create(NULL, TYPE_S390_PCI_HOST_BRIDGE);
>      object_property_add_child(qdev_get_machine(), TYPE_S390_PCI_HOST_BRIDGE,
>                                OBJECT(dev), NULL);
> diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
> index 7c253ff308c5..249011fd62f5 100644
> --- a/target/s390x/cpu_models.c
> +++ b/target/s390x/cpu_models.c
> @@ -1314,11 +1314,6 @@ static void register_types(void)
>  
>      /* init all bitmaps from gnerated data initially */
>      s390_init_feat_bitmap(qemu_max_cpu_feat_init, qemu_max_cpu_feat);
> -#ifndef CONFIG_USER_ONLY
> -    if (!pci_available) {
> -        clear_bit(S390_FEAT_ZPCI, qemu_max_cpu_feat);
> -    }
> -#endif
>      for (i = 0; i < ARRAY_SIZE(s390_cpu_defs); i++) {
>          s390_init_feat_bitmap(s390_cpu_defs[i].base_init,
>                                s390_cpu_defs[i].base_feat);
> diff --git a/target/s390x/gen-features.c b/target/s390x/gen-features.c
> index 70015eaaf5df..b0e9b271e228 100644
> --- a/target/s390x/gen-features.c
> +++ b/target/s390x/gen-features.c
> @@ -598,7 +598,6 @@ static uint16_t qemu_MAX[] = {
>      S390_FEAT_STFLE_53,
>      /* generates a dependency warning, leave it out for now */
>      S390_FEAT_MSA_EXT_5,
> -    /* only with CONFIG_PCI */
>      S390_FEAT_ZPCI,
>  };
>  
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index 9ff80c8461d0..15fdc168e1c5 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -2278,9 +2278,7 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
>      }
>  
>      /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
> -    if (pci_available) {
> -        set_bit(S390_FEAT_ZPCI, model->features);
> -    }
> +    set_bit(S390_FEAT_ZPCI, model->features);
>      set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
>  
>      if (s390_known_cpu_type(cpu_type)) {
> 

Re: [Qemu-devel] [PATCH] s390x: always provide pci support

[Cornelia Huck]

On Mon, 11 Feb 2019 15:05:46 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 11.02.2019 12:32, Cornelia Huck wrote:
> > We tried to make pci support optional on s390x in the past;
> > unfortunately, we still require the s390 phb to be created
> > unconditionally due to backwards compatibility issues.
> > 
> > Instead of sinking more effort into this (including compat
> > handling for older machines etc.) for non-obvious gains, let's
> > just make CONFIG_PCI something that is always set on s390x.
> > 
> > Note that you can still fence off pci for the _guest_ if you
> > provide a cpu model without the zpci feature.
> > 
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>  
> 
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> 
> The previous attempts of making it configurable caused more  pain than
> benefit.

I think we've reaped all the benefits of the attempt already (making
relevant instructions check for the zpci feature bit).

Re: [Qemu-devel] [PATCH] s390x: always provide pci support

[Cornelia Huck]

On Mon, 11 Feb 2019 12:32:55 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> We tried to make pci support optional on s390x in the past;
> unfortunately, we still require the s390 phb to be created
> unconditionally due to backwards compatibility issues.
> 
> Instead of sinking more effort into this (including compat
> handling for older machines etc.) for non-obvious gains, let's
> just make CONFIG_PCI something that is always set on s390x.
> 
> Note that you can still fence off pci for the _guest_ if you
> provide a cpu model without the zpci feature.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
> Follow-up patch to the discussion around "hw/s390x: Fix the function
> arguments in the pci stub file". I've done a quick sanity test with
> tcg only so far.
> ---
>  hw/s390x/Makefile.objs      |  3 +-
>  hw/s390x/s390-pci-stub.c    | 77 -------------------------------------
>  hw/s390x/s390-virtio-ccw.c  |  4 --
>  target/s390x/cpu_models.c   |  5 ---
>  target/s390x/gen-features.c |  1 -
>  target/s390x/kvm.c          |  4 +-
>  6 files changed, 2 insertions(+), 92 deletions(-)
>  delete mode 100644 hw/s390x/s390-pci-stub.c

Queued to s390-next.