Re: [PATCH v3 3/3] s390/setup : enable display support for KVM guest

[Thomas Huth]

On 19.02.2018 16:47, Farhan Ali wrote:
> The S390 architecture does not support any graphics hardware,
> but with the latest support for Virtio GPU in Linux and Virtio
> GPU emulation in QEMU, it's possible to enable graphics for
> S390 using the Virtio GPU device.
> 
> To enable display we need to enable the Linux Virtual Terminal (VT)
> layer for S390. But the VT subsystem initializes quite early
> at boot so we need a dummy console driver till the Virtio GPU
> driver is initialized and we can run the framebuffer console.
> 
> The framebuffer console over a Virtio GPU device can be run
> in combination with the serial SCLP console (default on S390).
> The SCLP console can still be accessed by management applications
> (eg: via Libvirt's virsh console).
> 
> Signed-off-by: Farhan Ali 
> Acked-by: Christian Borntraeger 
> ---
>  arch/s390/kernel/setup.c  | 2 ++
>  drivers/tty/Kconfig   | 2 +-
>  drivers/video/console/Kconfig | 2 +-
>  3 files changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Thomas Huth 

Re: [PATCH v3 3/3] s390/setup : enable display support for KVM guest

[Thomas Huth]

On 19.02.2018 16:47, Farhan Ali wrote:
> The S390 architecture does not support any graphics hardware,
> but with the latest support for Virtio GPU in Linux and Virtio
> GPU emulation in QEMU, it's possible to enable graphics for
> S390 using the Virtio GPU device.
> 
> To enable display we need to enable the Linux Virtual Terminal (VT)
> layer for S390. But the VT subsystem initializes quite early
> at boot so we need a dummy console driver till the Virtio GPU
> driver is initialized and we can run the framebuffer console.
> 
> The framebuffer console over a Virtio GPU device can be run
> in combination with the serial SCLP console (default on S390).
> The SCLP console can still be accessed by management applications
> (eg: via Libvirt's virsh console).
> 
> Signed-off-by: Farhan Ali 
> Acked-by: Christian Borntraeger 
> ---
>  arch/s390/kernel/setup.c  | 2 ++
>  drivers/tty/Kconfig   | 2 +-
>  drivers/video/console/Kconfig | 2 +-
>  3 files changed, 4 insertions(+), 2 deletions(-)

Reviewed-by: Thomas Huth 

[PATCH v3 3/3] s390/setup : enable display support for KVM guest

[Farhan Ali]

The S390 architecture does not support any graphics hardware,
but with the latest support for Virtio GPU in Linux and Virtio
GPU emulation in QEMU, it's possible to enable graphics for
S390 using the Virtio GPU device.

To enable display we need to enable the Linux Virtual Terminal (VT)
layer for S390. But the VT subsystem initializes quite early
at boot so we need a dummy console driver till the Virtio GPU
driver is initialized and we can run the framebuffer console.

The framebuffer console over a Virtio GPU device can be run
in combination with the serial SCLP console (default on S390).
The SCLP console can still be accessed by management applications
(eg: via Libvirt's virsh console).

Signed-off-by: Farhan Ali 
Acked-by: Christian Borntraeger 
---
 arch/s390/kernel/setup.c  | 2 ++
 drivers/tty/Kconfig   | 2 +-
 drivers/video/console/Kconfig | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index a6a91f0..f98a0f3 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -221,6 +221,8 @@ static void __init conmode_default(void)
SET_CONSOLE_SCLP;
 #endif
}
+   if (IS_ENABLED(CONFIG_VT) && IS_ENABLED(CONFIG_DUMMY_CONSOLE))
+   conswitchp = _con;
 }
 
 #ifdef CONFIG_CRASH_DUMP
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index b811442..5ca53fa 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -11,7 +11,7 @@ if TTY
 
 config VT
bool "Virtual terminal" if EXPERT
-   depends on !S390 && !UML
+   depends on !UML
select INPUT
default y
---help---
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 0023b16..7aa721e 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -9,7 +9,7 @@ config VGA_CONSOLE
depends on !4xx && !PPC_8xx && !SPARC && !M68K && !PARISC && !FRV && \
!SUPERH && !BLACKFIN && !AVR32 && !MN10300 && !CRIS && \
(!ARM || ARCH_FOOTBRIDGE || ARCH_INTEGRATOR || ARCH_NETWINDER) 
&& \
-   !ARM64 && !ARC && !MICROBLAZE && !OPENRISC
+   !ARM64 && !ARC && !MICROBLAZE && !OPENRISC && !S390
default y
help
  Saying Y here will allow you to use Linux in text mode through a
-- 
2.7.4

[PATCH v3 3/3] s390/setup : enable display support for KVM guest

[Farhan Ali]

The S390 architecture does not support any graphics hardware,
but with the latest support for Virtio GPU in Linux and Virtio
GPU emulation in QEMU, it's possible to enable graphics for
S390 using the Virtio GPU device.

To enable display we need to enable the Linux Virtual Terminal (VT)
layer for S390. But the VT subsystem initializes quite early
at boot so we need a dummy console driver till the Virtio GPU
driver is initialized and we can run the framebuffer console.

The framebuffer console over a Virtio GPU device can be run
in combination with the serial SCLP console (default on S390).
The SCLP console can still be accessed by management applications
(eg: via Libvirt's virsh console).

Signed-off-by: Farhan Ali 
Acked-by: Christian Borntraeger 
---
 arch/s390/kernel/setup.c  | 2 ++
 drivers/tty/Kconfig   | 2 +-
 drivers/video/console/Kconfig | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index a6a91f0..f98a0f3 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -221,6 +221,8 @@ static void __init conmode_default(void)
SET_CONSOLE_SCLP;
 #endif
}
+   if (IS_ENABLED(CONFIG_VT) && IS_ENABLED(CONFIG_DUMMY_CONSOLE))
+   conswitchp = _con;
 }
 
 #ifdef CONFIG_CRASH_DUMP
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index b811442..5ca53fa 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -11,7 +11,7 @@ if TTY
 
 config VT
bool "Virtual terminal" if EXPERT
-   depends on !S390 && !UML
+   depends on !UML
select INPUT
default y
---help---
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 0023b16..7aa721e 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -9,7 +9,7 @@ config VGA_CONSOLE
depends on !4xx && !PPC_8xx && !SPARC && !M68K && !PARISC && !FRV && \
!SUPERH && !BLACKFIN && !AVR32 && !MN10300 && !CRIS && \
(!ARM || ARCH_FOOTBRIDGE || ARCH_INTEGRATOR || ARCH_NETWINDER) 
&& \
-   !ARM64 && !ARC && !MICROBLAZE && !OPENRISC
+   !ARM64 && !ARC && !MICROBLAZE && !OPENRISC && !S390
default y
help
  Saying Y here will allow you to use Linux in text mode through a
-- 
2.7.4