Re: [Qemu-devel] [PATCH v4 07/11] pc-bios/s390-ccw: Add code for virtio feature negotiation

[Thomas Huth]

On 11.07.2017 16:23, Cornelia Huck wrote:
> On Tue, 11 Jul 2017 15:56:33 +0200
> Thomas Huth  wrote:
> 
>> The upcoming virtio-net driver needs to negotiate some features,
>> so we need the possibility to do this in the core virtio code.
>>
>> Signed-off-by: Thomas Huth 
>> ---
>>  pc-bios/s390-ccw/s390-ccw.h |  2 ++
>>  pc-bios/s390-ccw/virtio.c   | 23 +--
>>  pc-bios/s390-ccw/virtio.h   |  1 +
>>  3 files changed, 20 insertions(+), 6 deletions(-)
> 
> 
>> diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
>> index d733780..a00a320 100644
>> --- a/pc-bios/s390-ccw/virtio.h
>> +++ b/pc-bios/s390-ccw/virtio.h
>> @@ -251,6 +251,7 @@ struct VDev {
>>  ScsiDevice selected_scsi_device;
>>  uint64_t netboot_start_addr;
>>  uint32_t max_transfer;
>> +uint32_t guest_features[2];
> 
> Just 'features' might have been a better name, but:

I think it's clearer to call it guest_features ... in case we ever want
to store the host features, too.

>>  };
>>  typedef struct VDev VDev;
>>  
> 
> Reviewed-by: Cornelia Huck 

Thanks!

 Thomas

Re: [Qemu-devel] [PATCH v4 07/11] pc-bios/s390-ccw: Add code for virtio feature negotiation

[Cornelia Huck]

On Tue, 11 Jul 2017 15:56:33 +0200
Thomas Huth  wrote:

> The upcoming virtio-net driver needs to negotiate some features,
> so we need the possibility to do this in the core virtio code.
> 
> Signed-off-by: Thomas Huth 
> ---
>  pc-bios/s390-ccw/s390-ccw.h |  2 ++
>  pc-bios/s390-ccw/virtio.c   | 23 +--
>  pc-bios/s390-ccw/virtio.h   |  1 +
>  3 files changed, 20 insertions(+), 6 deletions(-)


> diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
> index d733780..a00a320 100644
> --- a/pc-bios/s390-ccw/virtio.h
> +++ b/pc-bios/s390-ccw/virtio.h
> @@ -251,6 +251,7 @@ struct VDev {
>  ScsiDevice selected_scsi_device;
>  uint64_t netboot_start_addr;
>  uint32_t max_transfer;
> +uint32_t guest_features[2];

Just 'features' might have been a better name, but:

>  };
>  typedef struct VDev VDev;
>  

Reviewed-by: Cornelia Huck 

[Qemu-devel] [PATCH v4 07/11] pc-bios/s390-ccw: Add code for virtio feature negotiation

[Thomas Huth]

The upcoming virtio-net driver needs to negotiate some features,
so we need the possibility to do this in the core virtio code.

Signed-off-by: Thomas Huth 
---
 pc-bios/s390-ccw/s390-ccw.h |  2 ++
 pc-bios/s390-ccw/virtio.c   | 23 +--
 pc-bios/s390-ccw/virtio.h   |  1 +
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index 6fdc858..25d4d21 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -44,6 +44,8 @@ typedef unsigned long long __u64;
 ((b) == 0 ? (a) : (MIN(a, b
 #endif
 
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
 #include "cio.h"
 #include "iplb.h"
 
diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c
index 9d9e61f..18fc5d1 100644
--- a/pc-bios/s390-ccw/virtio.c
+++ b/pc-bios/s390-ccw/virtio.c
@@ -12,6 +12,7 @@
 #include "s390-ccw.h"
 #include "virtio.h"
 #include "virtio-scsi.h"
+#include "bswap.h"
 
 #define VRING_WAIT_REPLY_TIMEOUT 3
 
@@ -249,8 +250,12 @@ int virtio_run(VDev *vdev, int vqid, VirtioCmd *cmd)
 
 void virtio_setup_ccw(VDev *vdev)
 {
-int i, cfg_size = 0;
+int i, rc, cfg_size = 0;
 unsigned char status = VIRTIO_CONFIG_S_DRIVER_OK;
+struct VirtioFeatureDesc {
+uint32_t features;
+uint8_t index;
+} __attribute__((packed)) feats;
 
 IPL_assert(virtio_is_supported(vdev->schid), "PE");
 /* device ID has been established now */
@@ -277,11 +282,17 @@ void virtio_setup_ccw(VDev *vdev)
 IPL_assert(run_ccw(vdev, CCW_CMD_READ_CONF, >config, cfg_size) == 0,
"Could not get block device configuration");
 
-/*
- * Skipping CCW_CMD_READ_FEAT. We're not doing anything fancy, and
- * we'll just stop dead anyway if anything does not work like we
- * expect it.
- */
+/* Feature negotiation */
+for (i = 0; i < ARRAY_SIZE(vdev->guest_features); i++) {
+feats.features = 0;
+feats.index = i;
+rc = run_ccw(vdev, CCW_CMD_READ_FEAT, , sizeof(feats));
+IPL_assert(rc == 0, "Could not get features bits");
+vdev->guest_features[i] &= bswap32(feats.features);
+feats.features = bswap32(vdev->guest_features[i]);
+rc = run_ccw(vdev, CCW_CMD_WRITE_FEAT, , sizeof(feats));
+IPL_assert(rc == 0, "Could not set features bits");
+}
 
 for (i = 0; i < vdev->nr_vqs; i++) {
 VqInfo info = {
diff --git a/pc-bios/s390-ccw/virtio.h b/pc-bios/s390-ccw/virtio.h
index d733780..a00a320 100644
--- a/pc-bios/s390-ccw/virtio.h
+++ b/pc-bios/s390-ccw/virtio.h
@@ -251,6 +251,7 @@ struct VDev {
 ScsiDevice selected_scsi_device;
 uint64_t netboot_start_addr;
 uint32_t max_transfer;
+uint32_t guest_features[2];
 };
 typedef struct VDev VDev;
 
-- 
1.8.3.1