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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v8 01/26] emul/vuart: introduce framework for UART emulators
From: Denis Mukhin <dmukhin@xxxxxxxx>
Introduce a driver framework to abstract UART emulators in the hypervisor.
That allows for architecture-independent handling of virtual UARTs in
the console driver and simplifies enabling new UART emulators.
The framework is built under CONFIG_VUART_FRAMEWORK, which will be
automatically enabled once the user enables any UART emulator.
Current implementation supports maximum of one vUART of each kind per
domain.
Use new domain_has_vuart() in the console driver code to check whether
to forward console input to the domain using vUART.
Enable console forwarding over vUART for hardware domains with a vUART.
That enables console forwarding to dom0 on x86, since console can be
forwarded only to Xen, dom0 and pvshim on x86 as of now.
Note: existing vUARTs are deliberately *not* hooked to the new framework
to minimize the scope of the patch: vpl011 (i.e. SBSA) emulator and
"vuart" (i.e. minimalistic MMIO-mapped dtuart for hwdoms on Arm) are
kept unmodified.
No functional changes for non-x86 architectures.
Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
xen/arch/arm/xen.lds.S | 1 +
xen/arch/ppc/xen.lds.S | 1 +
xen/arch/riscv/xen.lds.S | 1 +
xen/arch/x86/xen.lds.S | 1 +
xen/common/Kconfig | 2 +
xen/common/Makefile | 1 +
xen/common/emul/Kconfig | 6 ++
xen/common/emul/Makefile | 1 +
xen/common/emul/vuart/Kconfig | 6 ++
xen/common/emul/vuart/Makefile | 1 +
xen/common/emul/vuart/ns165x50.c | 0
xen/common/emul/vuart/vuart.c | 173 +++++++++++++++++++++++++++++++
xen/common/keyhandler.c | 3 +
xen/drivers/char/console.c | 6 +-
xen/include/xen/sched.h | 5 +
xen/include/xen/serial.h | 5 +
xen/include/xen/vuart.h | 115 ++++++++++++++++++++
xen/include/xen/xen.lds.h | 10 ++
18 files changed, 337 insertions(+), 1 deletion(-)
create mode 100644 xen/common/emul/Kconfig
create mode 100644 xen/common/emul/Makefile
create mode 100644 xen/common/emul/vuart/Kconfig
create mode 100644 xen/common/emul/vuart/Makefile
create mode 100644 xen/common/emul/vuart/ns165x50.c
create mode 100644 xen/common/emul/vuart/vuart.c
create mode 100644 xen/include/xen/vuart.h
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 613511390ff4..423b8e717539 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -58,6 +58,7 @@ SECTIONS
*(.rodata)
*(.rodata.*)
VPCI_ARRAY
+ VUART_ARRAY
*(.data.rel.ro)
*(.data.rel.ro.*)
diff --git a/xen/arch/ppc/xen.lds.S b/xen/arch/ppc/xen.lds.S
index 37256c8865a9..228dbe0055c1 100644
--- a/xen/arch/ppc/xen.lds.S
+++ b/xen/arch/ppc/xen.lds.S
@@ -52,6 +52,7 @@ SECTIONS
*(.rodata)
*(.rodata.*)
VPCI_ARRAY
+ VUART_ARRAY
*(.data.rel.ro)
*(.data.rel.ro.*)
diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
index d9375a961697..ca34974f5adf 100644
--- a/xen/arch/riscv/xen.lds.S
+++ b/xen/arch/riscv/xen.lds.S
@@ -49,6 +49,7 @@ SECTIONS
*(.rodata)
*(.rodata.*)
VPCI_ARRAY
+ VUART_ARRAY
*(.data.rel.ro)
*(.data.rel.ro.*)
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 8f943e11ead4..e57ab6ff74f3 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -123,6 +123,7 @@ SECTIONS
*(.rodata)
*(.rodata.*)
VPCI_ARRAY
+ VUART_ARRAY
*(.data.rel.ro)
*(.data.rel.ro.*)
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 5b289e444fa5..7f102a5ab3fc 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -675,4 +675,6 @@ config PM_STATS
Enable collection of performance management statistics to aid in
analyzing and tuning power/performance characteristics of the system
+source "common/emul/Kconfig"
+
endmenu
diff --git a/xen/common/Makefile b/xen/common/Makefile
index f69d47d18934..60f2d9087589 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_DEVICE_TREE_PARSE) += device-tree/
obj-$(CONFIG_IOREQ_SERVER) += dm.o
obj-y += domain.o
obj-y += domid.o
+obj-y += emul/
obj-$(CONFIG_HAS_SHARED_INFO) += event_2l.o
obj-y += event_channel.o
obj-$(CONFIG_EVTCHN_FIFO) += event_fifo.o
diff --git a/xen/common/emul/Kconfig b/xen/common/emul/Kconfig
new file mode 100644
index 000000000000..7c6764d1756b
--- /dev/null
+++ b/xen/common/emul/Kconfig
@@ -0,0 +1,6 @@
+menu "Domain Emulation Features"
+ visible if EXPERT
+
+source "common/emul/vuart/Kconfig"
+
+endmenu
diff --git a/xen/common/emul/Makefile b/xen/common/emul/Makefile
new file mode 100644
index 000000000000..ae0b575c3901
--- /dev/null
+++ b/xen/common/emul/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_VUART_FRAMEWORK) += vuart/
diff --git a/xen/common/emul/vuart/Kconfig b/xen/common/emul/vuart/Kconfig
new file mode 100644
index 000000000000..ce1b976b7da7
--- /dev/null
+++ b/xen/common/emul/vuart/Kconfig
@@ -0,0 +1,6 @@
+config VUART_FRAMEWORK
+ bool
+
+menu "UART Emulation"
+
+endmenu
diff --git a/xen/common/emul/vuart/Makefile b/xen/common/emul/vuart/Makefile
new file mode 100644
index 000000000000..97f792dc6641
--- /dev/null
+++ b/xen/common/emul/vuart/Makefile
@@ -0,0 +1 @@
+obj-y += vuart.o
diff --git a/xen/common/emul/vuart/ns165x50.c b/xen/common/emul/vuart/ns165x50.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/xen/common/emul/vuart/vuart.c b/xen/common/emul/vuart/vuart.c
new file mode 100644
index 000000000000..bd3b756fb4d6
--- /dev/null
+++ b/xen/common/emul/vuart/vuart.c
@@ -0,0 +1,173 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * UART emulator framework.
+ *
+ */
+
+#include <asm/types.h>
+
+#include <xen/err.h>
+#include <xen/resource.h>
+#include <xen/sched.h>
+#include <xen/vuart.h>
+#include <xen/xvmalloc.h>
+
+#define for_each_emulator(e) \
+ for ( e = vuart_array_start; e < vuart_array_end; e++ )
+
+extern const struct vuart_emulator vuart_array_start[];
+extern const struct vuart_emulator vuart_array_end[];
+
+static const struct vuart_emulator *
+vuart_match_by_compatible(const struct domain *d, const char *compat)
+{
+ const struct vuart_emulator *emulator;
+
+ for_each_emulator(emulator)
+ if ( emulator->compatible &&
+ !strncmp(compat, emulator->compatible,
+ strlen(emulator->compatible)) )
+ return emulator;
+
+ return NULL;
+}
+
+const static struct vuart *
+vuart_find_by_flags(const struct domain *d, unsigned int flags)
+{
+ const struct vuart *vuart = d->console->vuart;
+
+ if ( vuart && (vuart->info->flags & flags) )
+ return vuart;
+
+ return NULL;
+}
+
+struct vuart *vuart_find_by_resource(const struct domain *d,
+ unsigned int type,
+ unsigned long addr,
+ unsigned long size)
+{
+ struct vuart *vuart = d->console->vuart;
+
+ if ( vuart &&
+ (type & vuart->info->base_type) &&
+ addr >= vuart->info->base_addr &&
+ addr + size <= vuart->info->base_addr + vuart->info->size )
+ return vuart;
+
+ return NULL;
+}
+
+int vuart_init(struct domain *d, const struct vuart_info *info)
+{
+ const struct vuart_emulator *emulator;
+ struct vuart *vuart;
+ int rc;
+
+ if ( !info )
+ return 0; /* Nothing to do */
+
+ if ( d->console->vuart )
+ return -EBUSY;
+
+ emulator = vuart_match_by_compatible(d, info->compatible);
+ if ( !emulator )
+ return -ENODEV;
+
+ vuart = xzalloc(typeof(*vuart));
+ if ( !vuart )
+ return -ENOMEM;
+
+ vuart->info = xvzalloc(typeof(*vuart->info));
+ if ( !vuart->info )
+ {
+ rc = -ENOMEM;
+ goto err_out1;
+ }
+ memcpy(vuart->info, info, sizeof(*info));
+
+ vuart->vdev = emulator->alloc(d, vuart->info);
+ if ( IS_ERR(vuart->vdev) )
+ {
+ rc = PTR_ERR(vuart->vdev);
+ goto err_out2;
+ }
+
+ vuart->emulator = emulator;
+ vuart->owner = d;
+
+ d->console->input_allowed = true;
+ d->console->vuart = vuart;
+
+ return 0;
+
+ err_out2:
+ xvfree(vuart->info);
+ err_out1:
+ xvfree(vuart);
+
+ return rc;
+}
+
+/*
+ * Release any resources taken by UART emulators.
+ *
+ * NB: no flags are cleared, since currently exit() is called only during
+ * domain destroy.
+ */
+void vuart_deinit(struct domain *d)
+{
+ struct vuart *vuart = d->console->vuart;
+
+ if ( vuart )
+ {
+ vuart->emulator->free(vuart->vdev);
+ xvfree(vuart->info);
+ }
+
+ XVFREE(d->console->vuart);
+}
+
+/*
+ * Print emulated UART state on the console.
+ *
+ * Must be called under rcu_lock_domain().
+ */
+void vuart_dump_state(const struct domain *d)
+{
+ struct vuart *vuart = d->console->vuart;
+
+ if ( vuart && vuart->emulator->dump_state )
+ vuart->emulator->dump_state(vuart->vdev);
+}
+
+/*
+ * Put character to the first emulated UART's FIFO with the physical console
+ * forwarding enabled.
+ *
+ * Must be called under rcu_lock_domain().
+ */
+int vuart_put_rx(const struct domain *d, char c)
+{
+ const struct vuart *vuart = vuart_find_by_flags(d, VUART_CONSOLE_INPUT);
+
+ if ( vuart && vuart->emulator->put_rx )
+ return vuart->emulator->put_rx(vuart->vdev, c);
+
+ return -ENODEV;
+}
+
+bool domain_has_vuart(const struct domain *d)
+{
+ return vuart_find_by_flags(d, VUART_CONSOLE_INPUT);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/common/keyhandler.c b/xen/common/keyhandler.c
index 7103bf20a7c9..b5012c9cb26d 100644
--- a/xen/common/keyhandler.c
+++ b/xen/common/keyhandler.c
@@ -22,6 +22,7 @@
#include <xen/mm.h>
#include <xen/watchdog.h>
#include <xen/init.h>
+#include <xen/vuart.h>
#include <asm/div64.h>
static unsigned char keypress_key;
@@ -360,6 +361,8 @@ static void cf_check dump_domains(unsigned char key)
v->periodic_period / 1000000);
}
}
+
+ vuart_dump_state(d);
}
for_each_domain ( d )
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index e4df0bbc2eec..62ca32e5392a 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -33,6 +33,7 @@
#include <xen/dom0less-build.h>
#include <xen/sections.h>
#include <xen/consoled.h>
+#include <xen/vuart.h>
#ifdef CONFIG_X86
#include <asm/guest.h>
@@ -639,11 +640,12 @@ static void __serial_rx(char c)
if ( !d )
return;
- if ( is_hardware_domain(d) )
+ if ( is_hardware_domain(d) && !domain_has_vuart(d) )
{
/*
* Deliver input to the hardware domain buffer, unless it is
* already full.
+ * NB: must be the first check: hardware domain may have emulated UART.
*/
if ( (serial_rx_prod - serial_rx_cons) != SERIAL_RX_SIZE )
serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
@@ -654,6 +656,8 @@ static void __serial_rx(char c)
*/
send_global_virq(VIRQ_CONSOLE);
}
+ else if ( domain_has_vuart(d) )
+ rc = vuart_put_rx(d, c);
#ifdef CONFIG_SBSA_VUART_CONSOLE
else
/* Deliver input to the emulated UART. */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ce1fa636db36..4fa7f62490ca 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -24,6 +24,7 @@
#include <asm/atomic.h>
#include <asm/current.h>
#include <xen/vpci.h>
+#include <xen/vuart.h>
#include <xen/wait.h>
#include <public/xen.h>
#include <public/domctl.h>
@@ -382,6 +383,10 @@ struct domain_console {
unsigned int idx;
spinlock_t lock;
char buf[256];
+
+#ifdef CONFIG_VUART_FRAMEWORK
+ struct vuart *vuart;
+#endif
};
enum __packed domain_shutdown_state {
diff --git a/xen/include/xen/serial.h b/xen/include/xen/serial.h
index 3a71da767dd7..ec481893fede 100644
--- a/xen/include/xen/serial.h
+++ b/xen/include/xen/serial.h
@@ -32,10 +32,15 @@ enum serial_port_state {
struct vuart_info {
paddr_t base_addr; /* Base address of the UART */
+ unsigned int base_type; /* Base I/O resource type */
unsigned long size; /* Size of the memory region */
unsigned long data_off; /* Data register offset */
unsigned long status_off; /* Status register offset */
unsigned long status; /* Ready status value */
+ unsigned long flags; /* Emulation flags */
+ unsigned int irq; /* Emulated IRQ # */
+ char compatible[16]; /* Compatible string */
+ char name[16]; /* User-friendly name */
};
struct serial_port {
diff --git a/xen/include/xen/vuart.h b/xen/include/xen/vuart.h
new file mode 100644
index 000000000000..b5785b3c6b8f
--- /dev/null
+++ b/xen/include/xen/vuart.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * UART emulator framework.
+ *
+ */
+
+#ifndef XEN_VUART_H
+#define XEN_VUART_H
+
+#include <xen/serial.h>
+#include <public/xen.h>
+
+struct vuart_emulator;
+
+enum {
+ VUART_CONSOLE_INPUT = BIT(0, U), /* Physical console input forwarding. */
+};
+
+/*
+ * FIXME: #ifdef is temporary to avoid clash with
+ * arch/arm/include/asm/domain.h
+ */
+#ifdef CONFIG_VUART_FRAMEWORK
+struct vuart {
+ const struct vuart_emulator *emulator;
+ struct vuart_info *info;
+ struct domain *owner;
+ void *vdev;
+};
+#endif
+
+struct vuart_emulator {
+ /* UART compatible string. Cannot be NULL or empty. */
+ const char *compatible;
+
+ /*
+ * Allocate emulated UART state (RX/TX FIFOs, locks, initialize registers,
+ * hook I/O handlers, etc.)
+ * Cannot be NULL.
+ */
+ void *(*alloc)(struct domain *d, const struct vuart_info *info);
+
+ /*
+ * Release resources used to emulate UART state (flush RX/TX FIFOs, unhook
+ * I/O handlers, etc.).
+ * Cannot be NULL.
+ */
+ void (*free)(void *arg);
+
+ /*
+ * Print emulated UART state (e.g. emulated registers) on the diagnostic
+ * console.
+ * Can be NULL.
+ */
+ void (*dump_state)(void *arg);
+
+ /*
+ * Place character to the emulated RX FIFO.
+ * Used to forward physical console input to the guest OS.
+ * Can be NULL.
+ */
+ int (*put_rx)(void *arg, char c);
+};
+
+#define VUART_REGISTER(name, x) \
+ static const struct vuart_emulator name##_entry \
+ __used_section(".data.rel.ro.vuart") = x
+
+struct vuart *vuart_find_by_resource(const struct domain *d,
+ unsigned int type,
+ unsigned long addr,
+ unsigned long size);
+
+int vuart_put_rx(const struct domain *d, char c);
+
+#ifdef CONFIG_VUART_FRAMEWORK
+
+int vuart_init(struct domain *d, const struct vuart_info *info);
+void vuart_deinit(struct domain *d);
+void vuart_dump_state(const struct domain *d);
+bool domain_has_vuart(const struct domain *d);
+
+#else
+
+static inline int vuart_init(struct domain *d, const struct vuart_info *info)
+{
+ return 0;
+}
+
+static inline void vuart_deinit(struct domain *d)
+{
+}
+
+static inline void vuart_dump_state(const struct domain *d)
+{
+}
+
+static inline bool domain_has_vuart(const struct domain *d)
+{
+ return false;
+}
+
+#endif /* CONFIG_VUART_FRAMEWORK */
+
+#endif /* XEN_VUART_H */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
+
diff --git a/xen/include/xen/xen.lds.h b/xen/include/xen/xen.lds.h
index 958f8256b0fa..5e630d371471 100644
--- a/xen/include/xen/xen.lds.h
+++ b/xen/include/xen/xen.lds.h
@@ -231,6 +231,16 @@
#define VPCI_ARRAY
#endif
+#ifdef CONFIG_VUART_FRAMEWORK
+#define VUART_ARRAY \
+ . = ALIGN(POINTER_ALIGN); \
+ vuart_array_start = .; \
+ *(.data.rel.ro.vuart) \
+ vuart_array_end = .;
+#else
+#define VUART_ARRAY
+#endif
+
#define EX_TABLE \
. = ALIGN(4); \
__start___ex_table = .; \
--
2.56.0
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