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* [PATCH 04/14 v4] xen/arm: vpl011: Add support for vuart in libxl
@ 2017-06-06 10:03 Bhupinder Thakur
  0 siblings, 0 replies; 3+ messages in thread
From: Bhupinder Thakur @ 2017-06-06 10:03 UTC (permalink / raw)
  To: xen-devel; +Cc: Wei Liu, Julien Grall, Stefano Stabellini, Ian Jackson

An option is provided in libxl to enable/disable pl011 vuart while
creating a guest domain.

Libxl now suppots a generic vuart console and pl011 is a specific type.
In future support can be added for multiple vuart of different types.

User can enable pl011 vuart by adding the following line in the guest
configuration file:

vuart = "pl011"

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@linaro.org>
---

Changes since v3:
- Added a new config option CONFIG_VUART_CONSOLE to enable/disable vuart console
  support.
- Moved libxl_vuart_type to arch-arm part of libxl_domain_build_info
- Updated xl command help to mention new console type - vuart.

Changes since v2:
- Defined vuart option as an enum instead of a string.
- Removed the domain creation flag defined for vuart and the related code
  to pass on the information while domain creation. Now vpl011 is initialized
  independent of domain creation through new DOMCTL APIs.

 config/arm32.mk              |  1 +
 config/arm64.mk              |  1 +
 tools/libxl/libxl.h          |  6 ++++++
 tools/libxl/libxl_console.c  |  3 +++
 tools/libxl/libxl_internal.h |  3 +++
 tools/libxl/libxl_types.idl  |  7 +++++++
 tools/xl/Makefile            |  4 ++++
 tools/xl/xl_cmdtable.c       |  4 ++++
 tools/xl/xl_console.c        | 11 ++++++++++-
 tools/xl/xl_parse.c          |  8 ++++++++
 10 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/config/arm32.mk b/config/arm32.mk
index f95228e..b9f23fe 100644
--- a/config/arm32.mk
+++ b/config/arm32.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_32 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/config/arm64.mk b/config/arm64.mk
index aa45772..861d0a4 100644
--- a/config/arm64.mk
+++ b/config/arm64.mk
@@ -1,5 +1,6 @@
 CONFIG_ARM := y
 CONFIG_ARM_64 := y
+CONFIG_VUART_CONSOLE := y
 CONFIG_ARM_$(XEN_OS) := y
 
 CONFIG_XEN_INSTALL_SUFFIX :=
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index cf8687a..bcfbb6c 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -306,6 +306,12 @@
 #define LIBXL_HAVE_BUILDINFO_HVM_ACPI_LAPTOP_SLATE 1
 
 /*
+ * LIBXL_HAVE_VUART indicates that xenconsole/client supports
+ * virtual uart.
+ */
+#define LIBXL_HAVE_VUART 1
+
+/*
  * libxl ABI compatibility
  *
  * The only guarantee which libxl makes regarding ABI compatibility
diff --git a/tools/libxl/libxl_console.c b/tools/libxl/libxl_console.c
index 446e766..853be15 100644
--- a/tools/libxl/libxl_console.c
+++ b/tools/libxl/libxl_console.c
@@ -67,6 +67,9 @@ int libxl_console_exec(libxl_ctx *ctx, uint32_t domid, int cons_num,
     case LIBXL_CONSOLE_TYPE_SERIAL:
         cons_type_s = "serial";
         break;
+    case LIBXL_CONSOLE_TYPE_VUART:
+        cons_type_s = "vuart";
+        break;
     default:
         goto out;
     }
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 5d082c5..4e2c247 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1135,6 +1135,9 @@ typedef struct {
     uint32_t num_vmemranges;
 
     xc_domain_configuration_t config;
+
+    xen_pfn_t vuart_gfn;
+    evtchn_port_t vuart_port;
 } libxl__domain_build_state;
 
 _hidden int libxl__build_pre(libxl__gc *gc, uint32_t domid,
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 2204425..066aace 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -105,6 +105,7 @@ libxl_console_type = Enumeration("console_type", [
     (0, "UNKNOWN"),
     (1, "SERIAL"),
     (2, "PV"),
+    (3, "VUART"),
     ])
 
 libxl_disk_format = Enumeration("disk_format", [
@@ -240,6 +241,11 @@ libxl_checkpointed_stream = Enumeration("checkpointed_stream", [
     (2, "COLO"),
     ])
 
+libxl_vuart_type = Enumeration("vuart_type", [
+    (0, "unknown"),
+    (1, "pl011"),
+    ])
+
 #
 # Complex libxl types
 #
@@ -580,6 +586,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
 
 
     ("arch_arm", Struct(None, [("gic_version", libxl_gic_version),
+                               ("vuart", libxl_vuart_type),
                               ])),
     # Alternate p2m is not bound to any architecture or guest type, as it is
     # supported by x86 HVM and ARM support is planned.
diff --git a/tools/xl/Makefile b/tools/xl/Makefile
index e16f877..d7c4927 100644
--- a/tools/xl/Makefile
+++ b/tools/xl/Makefile
@@ -15,6 +15,10 @@ LDFLAGS += $(PTHREAD_LDFLAGS)
 CFLAGS_XL += $(CFLAGS_libxenlight)
 CFLAGS_XL += -Wshadow
 
+ifeq ($(CONFIG_VUART_CONSOLE),y)
+CFLAGS_XL += -DCONFIG_VUART_CONSOLE
+endif
+
 XL_OBJS = xl.o xl_cmdtable.o xl_sxp.o xl_utils.o
 XL_OBJS += xl_tmem.o xl_parse.o xl_cpupool.o xl_flask.o
 XL_OBJS += xl_vtpm.o xl_block.o xl_nic.o xl_usb.o
diff --git a/tools/xl/xl_cmdtable.c b/tools/xl/xl_cmdtable.c
index 30eb93c..14f7a50 100644
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -133,7 +133,11 @@ struct cmd_spec cmd_table[] = {
       &main_console, 0, 0,
       "Attach to domain's console",
       "[options] <Domain>\n"
+#ifdef CONFIG_VUART_CONSOLE
+      "-t <type>       console type, pv , serial or vuart\n"
+#else
       "-t <type>       console type, pv or serial\n"
+#endif
       "-n <number>     console number"
     },
     { "vncviewer",
diff --git a/tools/xl/xl_console.c b/tools/xl/xl_console.c
index 0508dda..d6ca93f 100644
--- a/tools/xl/xl_console.c
+++ b/tools/xl/xl_console.c
@@ -27,6 +27,11 @@ int main_console(int argc, char **argv)
     uint32_t domid;
     int opt = 0, num = 0;
     libxl_console_type type = 0;
+#ifdef CONFIG_VUART_CONSOLE
+    char *console_names = "pv, serial, vuart";
+#else
+    char *console_names = "pv, serial";
+#endif
 
     SWITCH_FOREACH_OPT(opt, "n:t:", NULL, "console", 1) {
     case 't':
@@ -34,8 +39,12 @@ int main_console(int argc, char **argv)
             type = LIBXL_CONSOLE_TYPE_PV;
         else if (!strcmp(optarg, "serial"))
             type = LIBXL_CONSOLE_TYPE_SERIAL;
+#ifdef CONFIG_VUART_CONSOLE
+        else if (!strcmp(optarg, "vuart"))
+            type = LIBXL_CONSOLE_TYPE_VUART;
+#endif
         else {
-            fprintf(stderr, "console type supported are: pv, serial\n");
+            fprintf(stderr, "console type supported are: %s\n", console_names);
             return EXIT_FAILURE;
         }
         break;
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 856a304..37581ef 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -916,6 +916,14 @@ void parse_config_data(const char *config_source,
     if (!xlu_cfg_get_long (config, "maxvcpus", &l, 0))
         b_info->max_vcpus = l;
 
+    if (!xlu_cfg_get_string(config, "vuart", &buf, 0)) {
+        if (libxl_vuart_type_from_string(buf, &b_info->arch_arm.vuart)) {
+            fprintf(stderr, "ERROR: invalid value \"%s\" for \"vuart\"\n",
+                    buf);
+            exit(1);
+        }
+    }
+
     parse_vnuma_config(config, b_info);
 
     /* Set max_memkb to target_memkb and max_vcpus to avail_vcpus if
-- 
2.7.4


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^ permalink raw reply related	[flat|nested] 3+ messages in thread
* [PATCH 00/14 v4] PL011 emulation support in Xen
@ 2017-06-06 17:25 Bhupinder Thakur
  2017-06-06 17:25 ` [PATCH 04/14 v4] xen/arm: vpl011: Add support for vuart in libxl Bhupinder Thakur
  0 siblings, 1 reply; 3+ messages in thread
From: Bhupinder Thakur @ 2017-06-06 17:25 UTC (permalink / raw)
  To: xen-devel; +Cc: Wei Liu, Julien Grall, Stefano Stabellini, Ian Jackson

PL011 emulation for guests in Xen
===================================
Linaro has published VM System specification for ARM Processors, which
provides a set of guidelines for both guest OS and hypervisor implementations, 
such that building OS images according to these guidelines guarantees
that those images can also run on hypervisors compliant with this specification.

One of the spec requirements is that the hypervisor must provide an
emulated PL011 UART as a serial console which meets the minimum requirements in 
SBSA UART as defined in appendix B of the following 
ARM Server Base Architecture Document:

https://static.docs.arm.com/den0029/a/Server_Base_System_Architecture_v3_1_ARM_DEN_0029A.pdf.

This feature allows the Xen guests to use SBSA compliant pl011 UART as 
as a console. 

Note that SBSA pl011 UART is a subset of full featured ARM pl011 UART and
supports only a subset of registers as mentioned below. It does not support
rx/tx DMA.

Currently, Xen supports paravirtualized (aka PV console) and an emulated serial 
consoles. This feature will expose an emulated SBSA pl011 UART console to the
guest, which a user can access using xenconsole.

The device tree passed to the guest VM will contain the pl011 MMIO address 
range and an irq for receiving rx/tx pl011 interrupts. The device tree format 
is specified in Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt.

The Xen hypervisor will expose two types of interfaces to the backend and domU. 

The interface exposed to domU will be an emulated pl011 UART by emulating the 
access to the following pl011 registers by the guest.

- Data register (DR)            - RW
- Raw interrupt status register (RIS)   - RO
- Masked interrupt status register (MIS)- RO
- Interrupt Mask (IMSC)         - RW
- Interrupt Clear (ICR)         - WO

It will also inject the pl011 interrupts to the guest in the following 
conditions:

- incoming data in the rx buffer for the guest
- there is space in the tx buffer for the guest to write more data

The interface exposed to the backend will be the same PV console interface, 
which minimizes the changes required in xenconsole to support a new pl011 console.

This interface has rx and tx ring buffers and an event channel for 
sending/receiving events from the backend. 

So essentially Xen handles the data on behalf of domU and the backend. Any data 
written by domU is captured by Xen and written to the TX (OUT) ring buffer 
and a pl011 event is raised to the backend to read the TX ring buffer.
 
Similarly on reciving a pl011 event, Xen injects an interrupt to guest to
indicate there is data available in the RX (IN) ring buffer.

The pl011 UART state is completely captured in the set of registers 
mentioned above and this state is updated everytime there is an event from 
the backend or there is register read/write access from domU. 

For example, if domU has masked the rx interrupt in the IMSC register, then Xen 
will not inject an interrupt to guest and will just update the RIS register. 
Once the interrupt is unmasked by guest, the interrupt will be delivered to the 
guest.

Changes summary:

Xen Hypervisor
===============

1. Add emulation code to emulate read/write access to pl011 registers and pl011 
   interrupts:
    - It emulates DR read/write by reading and writing from/to the IN and 
      OUT ring buffers and raising an event to dom0 when there is data in 
      the OUT ring buffer and injecting an interrupt to the guest when there 
      is data in the IN ring buffer.
    - Other registers are related to interrupt management and essentially 
      control when interrupts are delivered to the guest.

2. Add a new domctl API to initialize vpl011 emulation in Xen.

3. Enable vpl011 emulation for a domain based on a libxl option passed during 
   domain creation.

Toolstack
==========

1. Add a new option "vuart" in the domU configuration file to enable/disable vuart.

2. Create a SBSA UART DT node in the guest device tree. It uses a fixed
   vpl011 SPI IRQ number and MMIO address.

3. Call vpl011 init DOMCTL API to enable vpl011 emulation.

5. Add a new vuart xenstore node, which contains:
    - ring-ref
    - event channel
    - buffer limit
    - type

Xenconsoled
============

1. Split the domain structure to support multiple consoles.

2. Modify different APIs such as buffer_append() etc. to operate on the 
   console structure.
   
3. Add support for handling multiple consoles.

4. Add support for vuart console:

The vpl011 changes available at the following repo:

url: ssh://git@git.linaro.org:/people/bhupinder.thakur/xen.git
branch: vpl011_v4

There are some TBD items which need to be looked at in the future:

1. Currently UEFI firmware logs the output to hvc console only. How can 
   UEFI firmware be made aware of pl011 console and how it can use it
   as a console instead of hvc.
2. Linux seems to have hvc console as the default console i.e. if no
   console is specified then it uses hvc as the console. How can an 
   option be provided in Linux to select either hvc or pl011 as the 
   default console.

3. ACPI support for pl011 device.

CC: ij
CC: wl
CC: ss
CC: jg
CC: kw

Bhupinder Thakur (14):
  xen/arm: vpl011: Move vgic register access functions to vreg.h
  xen/arm: vpl011: Define generic vreg_reg* access functions in vreg.h
  xen/arm: vpl011: Add pl011 uart emulation in Xen
  xen/arm: vpl011: Add support for vuart in libxl
  xen/arm: vpl011: Allocate a new GFN in the toolstack for vuart
  xen/arm: vpl011: Add a new domctl API to initialize vpl011
  xen/arm: vpl011: Add a new vuart node in the xenstore
  xen/arm: vpl011: Modify xenconsole to define and use a new console    
    structure
  xen/arm: vpl011: Modify xenconsole functions to take console structure
    as input
  xen/arm: vpl011: Modify xenconsole to support multiple consoles
  xen/arm: vpl011: Add support for vuart console in xenconsole
  xen/arm: vpl011: Add a new vuart console type to xenconsole client
  xen/arm: vpl011: Add a pl011 uart DT node in the guest device tree
  xen/arm: vpl011: Update documentation for vuart console support

 config/arm32.mk                      |   1 +
 config/arm64.mk                      |   1 +
 docs/man/xl.cfg.pod.5.in             |   9 +
 docs/misc/console.txt                |  44 ++-
 tools/console/Makefile               |   4 +-
 tools/console/client/main.c          |  25 +-
 tools/console/daemon/io.c            | 544 ++++++++++++++++++++++++-----------
 tools/libxc/include/xc_dom.h         |   3 +
 tools/libxc/include/xenctrl.h        |  17 ++
 tools/libxc/xc_dom_arm.c             |  12 +-
 tools/libxc/xc_dom_boot.c            |   2 +
 tools/libxc/xc_domain.c              |  23 ++
 tools/libxl/libxl.h                  |   6 +
 tools/libxl/libxl_arch.h             |   7 +
 tools/libxl/libxl_arm.c              |  71 ++++-
 tools/libxl/libxl_console.c          |  47 +++
 tools/libxl/libxl_create.c           |  12 +-
 tools/libxl/libxl_device.c           |   9 +-
 tools/libxl/libxl_dom.c              |   8 +-
 tools/libxl/libxl_internal.h         |   7 +
 tools/libxl/libxl_types.idl          |   7 +
 tools/libxl/libxl_types_internal.idl |   1 +
 tools/libxl/libxl_x86.c              |   8 +
 tools/xl/Makefile                    |   4 +
 tools/xl/xl_cmdtable.c               |   4 +
 tools/xl/xl_console.c                |  11 +-
 tools/xl/xl_parse.c                  |   8 +
 xen/arch/arm/Kconfig                 |   5 +
 xen/arch/arm/Makefile                |   1 +
 xen/arch/arm/domain.c                |   2 +
 xen/arch/arm/domctl.c                |  44 ++-
 xen/arch/arm/vgic-v2.c               |  28 +-
 xen/arch/arm/vgic-v3.c               |  40 +--
 xen/arch/arm/vpl011.c                | 418 +++++++++++++++++++++++++++
 xen/include/asm-arm/domain.h         |   6 +
 xen/include/asm-arm/pl011-uart.h     |   2 +
 xen/include/asm-arm/vgic.h           | 111 +------
 xen/include/asm-arm/vpl011.h         |  74 +++++
 xen/include/asm-arm/vreg.h           | 109 +++++++
 xen/include/public/arch-arm.h        |   6 +
 xen/include/public/domctl.h          |  12 +
 xen/include/public/io/console.h      |   4 +
 42 files changed, 1421 insertions(+), 336 deletions(-)
 create mode 100644 xen/arch/arm/vpl011.c
 create mode 100644 xen/include/asm-arm/vpl011.h

-- 
2.7.4


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2017-06-06 10:03 [PATCH 04/14 v4] xen/arm: vpl011: Add support for vuart in libxl Bhupinder Thakur
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2017-06-06 17:25 [PATCH 00/14 v4] PL011 emulation support in Xen Bhupinder Thakur
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2017-06-06 23:07   ` Stefano Stabellini

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