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xenvm: drivers: serial: Implement serial interface to Xen PV console

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This commit adds minimal support of Xen hypervisor console via UART-like
driver. Implementation allows to use poll_in/poll_out char interface for
uart_console.c driver directly to HV console instead of using Xen
virtual PL011 UART. Future implementation will support interrupt driven
interface on Xen event channels, currently it is under development.

Also this commit introduces early console_io Xen interface, which allows
to receive printk/stdout messages quickly after start, but requires Xen,
built with CONFIG_DEBUG option.

Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
This commit is contained in:
Dmytro Firsov 2021-07-02 11:31:56 +03:00 committed by Carles Cufí
parent c4ab278688
commit d9a3efb834
13 changed files with 348 additions and 2 deletions
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8
CODEOWNERS
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@ -24,6 +24,7 @@
/arch/arm/core/aarch32/cortex_a_r/ @MaureenHelm @galak @ioannisg @bbolen @stephanosio
/arch/arm64/ @carlocaione
/arch/arm64/core/cortex_r/ @povergoing
/arch/arm64/core/xen/ @lorc @firscity
/arch/common/ @ioannisg @andyross
/soc/arc/snps_*/ @abrodkin @ruuddw @evgeniy-paltsev
/soc/nios2/ @nashif
@ -60,7 +61,7 @@
/soc/arm64/qemu_cortex_a53/ @carlocaione
/soc/arm64/bcm_vk/ @abhishek-brcm
/soc/arm64/nxp_layerscape/ @JiafeiPan
/soc/arm64/xenvm/ @lorc
/soc/arm64/xenvm/ @lorc @firscity
/soc/arm64/arm/ @povergoing
/soc/arm64/arm/fvp_aemv8a/ @carlocaione
/submanifests/* @mbolivar-nordic
@ -166,7 +167,7 @@
/boards/arm64/qemu_cortex_a53/ @carlocaione
/boards/arm64/bcm958402m2_a72/ @abhishek-brcm
/boards/arm64/nxp_ls1046ardb/ @JiafeiPan
/boards/arm64/xenvm/ @lorc
/boards/arm64/xenvm/ @lorc @firscity
/boards/arm64/fvp_baser_aemv8r/ @povergoing
/boards/arm64/fvp_base_revc_2xaemv8a/ @carlocaione
/boards/arm64/intel_socfpga_agilex_socdk/ @siclim @ngboonkhai
@ -343,6 +344,8 @@
/drivers/serial/serial_test.c @str4t0m
/drivers/serial/*esp32c3* @uLipe
/drivers/serial/*esp32s2* @glaubermaroto
/drivers/serial/Kconfig.xen @lorc @firscity
/drivers/serial/uart_hvc_xen.c @lorc @firscity
/drivers/disk/ @jfischer-no
/drivers/disk/sdmmc_sdhc.h @JunYangNXP
/drivers/disk/sdmmc_spi.c @JunYangNXP
@ -389,6 +392,7 @@
/drivers/wifi/eswifi/ @loicpoulain @nandojve
/drivers/wifi/winc1500/ @kludentwo
/drivers/virtualization/ @tbursztyka
/drivers/xen/ @lorc @firscity
/dts/arc/ @abrodkin @ruuddw @iriszzw @evgeniy-paltsev
/dts/arm/acsip/ @NorthernDean
/dts/arm/atmel/sam4e* @nandojve

1
drivers/CMakeLists.txt
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@ -63,3 +63,4 @@ add_subdirectory_ifdef(CONFIG_BBRAM bbram)
add_subdirectory_ifdef(CONFIG_FPGA fpga)
add_subdirectory_ifdef(CONFIG_PINCTRL pinctrl)
add_subdirectory_ifdef(CONFIG_MBOX mbox)
add_subdirectory_ifdef(CONFIG_BOARD_XENVM xen)

1
drivers/serial/CMakeLists.txt
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@ -45,6 +45,7 @@ zephyr_library_sources_ifdef(CONFIG_UART_RCAR uart_rcar.c)
zephyr_library_sources_ifdef(CONFIG_UART_XEC uart_mchp_xec.c)
zephyr_library_sources_ifdef(CONFIG_UART_NEORV32 uart_neorv32.c)
zephyr_library_sources_ifdef(CONFIG_USART_GD32 usart_gd32.c)
zephyr_library_sources_ifdef(CONFIG_UART_XEN_HVC uart_hvc_xen.c)
zephyr_library_sources_ifdef(CONFIG_USERSPACE uart_handlers.c)

2
drivers/serial/Kconfig
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@ -171,4 +171,6 @@ source "drivers/serial/Kconfig.test"
source "drivers/serial/Kconfig.neorv32"
source "drivers/serial/Kconfig.xen"
endif # SERIAL

30
drivers/serial/Kconfig.xen Normal file
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@ -0,0 +1,30 @@
# Xen hypervisor console via UART setup
#
# Copyright (c) 2021 EPAM Systems
# SPDX-License-Identifier: Apache-2.0
#
config UART_XEN_HVC
bool "Xen hypervisor console UART Driver"
select SERIAL_HAS_DRIVER
depends on BOARD_XENVM
default y
help
Enable Xen hypervisor console driver.
config XEN_HVC_INIT_PRIORITY
int "Xen hypervisor console init priority"
depends on UART_XEN_HVC
default 55
help
Set init priority for Xen HVC, should be inited before UART
console driver (HVC gets inited on PRE_KERNEL_1 stage).
config XEN_EARLY_CONSOLEIO
bool "Early printk/stdout through console_io Xen interface"
depends on BOARD_XENVM
default n
help
Enable setting of console_io symbol hook for stdout and printk.
Log output will become available on PRE_KERNEL_1 stage. Requires
Xen, compiled with CONFIG_DEBUG flag.

172
drivers/serial/uart_hvc_xen.c Normal file
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@ -0,0 +1,172 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <arch/arm64/hypercall.h>
#include <xen/console.h>
#include <xen/events.h>
#include <xen/generic.h>
#include <xen/hvm.h>
#include <xen/public/io/console.h>
#include <xen/public/xen.h>
#include <device.h>
#include <init.h>
#include <kernel.h>
#include <logging/log.h>
#include <sys/device_mmio.h>
LOG_MODULE_REGISTER(uart_hvc_xen);
static struct hvc_xen_data hvc_data = {0};
static int read_from_ring(const struct device *dev, char *str, int len)
{
int recv = 0;
struct hvc_xen_data *hvc_data = dev->data;
XENCONS_RING_IDX cons = hvc_data->intf->in_cons;
XENCONS_RING_IDX prod = hvc_data->intf->in_prod;
XENCONS_RING_IDX in_idx = 0;
compiler_barrier();
__ASSERT((prod - cons) <= sizeof(hvc_data->intf->in),
"Invalid input ring buffer");
while (cons != prod && recv < len) {
in_idx = MASK_XENCONS_IDX(cons, hvc_data->intf->in);
str[recv] = hvc_data->intf->in[in_idx];
recv++;
cons++;
}
compiler_barrier();
hvc_data->intf->in_cons = cons;
notify_evtchn(hvc_data->evtchn);
return recv;
}
static int write_to_ring(const struct device *dev, const char *str, int len)
{
int sent = 0;
struct hvc_xen_data *hvc_data = dev->data;
XENCONS_RING_IDX cons = hvc_data->intf->out_cons;
XENCONS_RING_IDX prod = hvc_data->intf->out_prod;
XENCONS_RING_IDX out_idx = 0;
compiler_barrier();
__ASSERT((prod - cons) <= sizeof(hvc_data->intf->out),
"Invalid output ring buffer");
while ((sent < len) && ((prod - cons) < sizeof(hvc_data->intf->out))) {
out_idx = MASK_XENCONS_IDX(prod, hvc_data->intf->out);
hvc_data->intf->out[out_idx] = str[sent];
prod++;
sent++;
}
compiler_barrier();
hvc_data->intf->out_prod = prod;
if (sent) {
notify_evtchn(hvc_data->evtchn);
}
return sent;
}
static int xen_hvc_poll_in(const struct device *dev,
unsigned char *c)
{
int ret = 0;
char temp;
ret = read_from_ring(dev, &temp, sizeof(temp));
if (!ret) {
/* Char was not received */
return -1;
}
*c = temp;
return 0;
}
static void xen_hvc_poll_out(const struct device *dev,
unsigned char c)
{
/* Not a good solution (notifying HV every time), but needed for poll_out */
(void) write_to_ring(dev, &c, sizeof(c));
}
static const struct uart_driver_api xen_hvc_api = {
.poll_in = xen_hvc_poll_in,
.poll_out = xen_hvc_poll_out,
};
int xen_console_init(const struct device *dev)
{
int ret = 0;
uint64_t console_pfn = 0;
uintptr_t console_addr = 0;
struct hvc_xen_data *data = dev->data;
data->dev = dev;
ret = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &data->evtchn);
if (ret) {
LOG_ERR("%s: failed to get Xen console evtchn, ret = %d\n",
__func__, ret);
return ret;
}
ret = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &console_pfn);
if (ret) {
LOG_ERR("%s: failed to get Xen console PFN, ret = %d\n",
__func__, ret);
return ret;
}
console_addr = (uintptr_t) (console_pfn << XEN_PAGE_SHIFT);
device_map(DEVICE_MMIO_RAM_PTR(dev), console_addr, XEN_PAGE_SIZE,
K_MEM_CACHE_WB);
data->intf = (struct xencons_interface *) DEVICE_MMIO_GET(dev);
LOG_INF("Xen HVC inited successfully\n");
return 0;
}
DEVICE_DT_DEFINE(DT_NODELABEL(xen_hvc), xen_console_init, NULL, &hvc_data,
NULL, PRE_KERNEL_1, CONFIG_XEN_HVC_INIT_PRIORITY,
&xen_hvc_api);
#ifdef CONFIG_XEN_EARLY_CONSOLEIO
extern void __printk_hook_install(int (*fn)(int));
extern void __stdout_hook_install(int (*fn)(int));
int xen_consoleio_putc(int c)
{
char symbol = (char) c;
HYPERVISOR_console_io(CONSOLEIO_write, sizeof(symbol), &symbol);
return c;
}
int consoleio_hooks_set(const struct device *dev)
{
ARG_UNUSED(dev);
/* Will be replaced with poll_in/poll_out by uart_console.c later on boot */
__stdout_hook_install(xen_consoleio_putc);
__printk_hook_install(xen_consoleio_putc);
return 0;
}
SYS_INIT(consoleio_hooks_set, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
#endif /* CONFIG_XEN_EARLY_CONSOLEIO */

5
drivers/xen/CMakeLists.txt Normal file
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@ -0,0 +1,5 @@
# SPDX-License-Identifier: Apache-2.0
# Copyright (c) 2021 EPAM Systems
zephyr_sources(hvm.c)
zephyr_sources(events.c)

25
drivers/xen/events.c Normal file
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@ -0,0 +1,25 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <arch/arm64/hypercall.h>
#include <xen/public/xen.h>
#include <xen/public/event_channel.h>
#include <xen/events.h>
void notify_evtchn(evtchn_port_t port)
{
struct evtchn_send send;
if (port >= EVTCHN_2L_NR_CHANNELS) {
printk("%s: trying to send notify for invalid evtchn #%u\n",
__func__, port);
return;
}
send.port = port;
HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
}

39
drivers/xen/hvm.c Normal file
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@ -0,0 +1,39 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <arch/arm64/hypercall.h>
#include <xen/hvm.h>
#include <xen/public/hvm/hvm_op.h>
#include <xen/public/hvm/params.h>
#include <kernel.h>
int hvm_set_parameter(int idx, uint64_t value)
{
struct xen_hvm_param xhv;
xhv.domid = DOMID_SELF;
xhv.index = idx;
xhv.value = value;
return HYPERVISOR_hvm_op(HVMOP_set_param, &xhv);
}
int hvm_get_parameter(int idx, uint64_t *value)
{
int ret = 0;
struct xen_hvm_param xhv;
xhv.domid = DOMID_SELF;
xhv.index = idx;
ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
if (ret < 0)
return ret;
*value = xhv.value;
return ret;
}

23
include/xen/console.h Normal file
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@ -0,0 +1,23 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef __XEN_CONSOLE_H__
#define __XEN_CONSOLE_H__
#include <init.h>
#include <device.h>
#include <drivers/uart.h>
#include <sys/device_mmio.h>
struct hvc_xen_data {
DEVICE_MMIO_RAM; /* should be first */
const struct device *dev;
struct xencons_interface *intf;
uint64_t evtchn;
};
int xen_console_init(const struct device *dev);
#endif /* __XEN_CONSOLE_H__ */

13
include/xen/events.h Normal file
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@ -0,0 +1,13 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef __XEN_EVENTS_H__
#define __XEN_EVENTS_H__
#include <xen/public/event_channel.h>
void notify_evtchn(evtchn_port_t port);
#endif /* __XEN_EVENTS_H__ */

14
include/xen/generic.h Normal file
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@ -0,0 +1,14 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef __XEN_GENERIC_H__
#define __XEN_GENERIC_H__
#include <xen/public/xen.h>
#define XEN_PAGE_SIZE 4096
#define XEN_PAGE_SHIFT 12
#endif /* __XEN_GENERIC_H__ */

17
include/xen/hvm.h Normal file
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@ -0,0 +1,17 @@
/*
* Copyright (c) 2021 EPAM Systems
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef __XEN_HVM_H__
#define __XEN_HVM_H__
#include <xen/public/hvm/hvm_op.h>
#include <xen/public/hvm/params.h>
#include <kernel.h>
int hvm_set_parameter(int idx, uint64_t value);
int hvm_get_parameter(int idx, uint64_t *value);
#endif /* __XEN_HVM_H__ */