|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v5 03/15] emul/ns16x50: implement emulator stub
From: Denis Mukhin <dmukhin@xxxxxxxx>
The change is the first on the way on introducing minimally functional
NS16550-compatible UART emulator.
Define UART state and a set of emulated registers.
Implement alloc/free vUART hooks.
Stub out I/O port handler.
Add initialization of the NS16x50-compatible UART emulator state machine.
Plumb debug logging.
Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
Changes since v4:
- new patch
---
xen/arch/x86/hvm/hvm.c | 20 ++
xen/common/emul/vuart/Kconfig | 18 ++
xen/common/emul/vuart/Makefile | 1 +
xen/common/emul/vuart/ns16x50.c | 362 ++++++++++++++++++++++++++++++++
xen/include/xen/sched.h | 4 +
5 files changed, 405 insertions(+)
create mode 100644 xen/common/emul/vuart/ns16x50.c
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 23bd7f078a1d..26760cf995df 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -28,6 +28,7 @@
#include <xen/softirq.h>
#include <xen/trace.h>
#include <xen/vm_event.h>
+#include <xen/vuart.h>
#include <xen/vpci.h>
#include <xen/wait.h>
#include <xen/warning.h>
@@ -689,6 +690,21 @@ int hvm_domain_initialise(struct domain *d,
if ( rc != 0 )
goto fail1;
+ if ( IS_ENABLED(CONFIG_VUART_NS16X50) )
+ {
+ struct vuart_info info = {
+ .name = "COM2",
+ .compatible = "ns16550",
+ .base_addr = 0x2f8,
+ .size = 8,
+ .irq = 3,
+ };
+
+ rc = vuart_init(d, &info);
+ if ( rc )
+ goto out_vioapic_deinit;
+ }
+
stdvga_init(d);
rtc_init(d);
@@ -712,6 +728,8 @@ int hvm_domain_initialise(struct domain *d,
return 0;
fail2:
+ vuart_deinit(d);
+ out_vioapic_deinit:
vioapic_deinit(d);
fail1:
if ( is_hardware_domain(d) )
@@ -774,6 +792,8 @@ void hvm_domain_destroy(struct domain *d)
if ( hvm_funcs.domain_destroy )
alternative_vcall(hvm_funcs.domain_destroy, d);
+ vuart_deinit(d);
+
vioapic_deinit(d);
XFREE(d->arch.hvm.pl_time);
diff --git a/xen/common/emul/vuart/Kconfig b/xen/common/emul/vuart/Kconfig
index ce1b976b7da7..539e6d5e4fc7 100644
--- a/xen/common/emul/vuart/Kconfig
+++ b/xen/common/emul/vuart/Kconfig
@@ -3,4 +3,22 @@ config VUART_FRAMEWORK
menu "UART Emulation"
+config VUART_NS16X50
+ bool "NS16550-compatible UART Emulator" if EXPERT
+ depends on X86 && HVM
+ select VUART_FRAMEWORK
+ help
+ In-hypervisor NS16x50 UART emulation.
+
+ Only legacy PC COM2 port is emulated.
+
+ This is strictly for testing purposes (such as early HVM guest
console),
+ and not appropriate for use in production.
+
+config VUART_NS16X50_DEBUG
+ bool "NS16550-compatible UART Emulator Debugging"
+ depends on VUART_NS16X50 && DEBUG
+ help
+ Enable development debugging.
+
endmenu
diff --git a/xen/common/emul/vuart/Makefile b/xen/common/emul/vuart/Makefile
index 97f792dc6641..fe904f6cb65d 100644
--- a/xen/common/emul/vuart/Makefile
+++ b/xen/common/emul/vuart/Makefile
@@ -1 +1,2 @@
obj-y += vuart.o
+obj-$(CONFIG_VUART_NS16X50) += ns16x50.o
diff --git a/xen/common/emul/vuart/ns16x50.c b/xen/common/emul/vuart/ns16x50.c
new file mode 100644
index 000000000000..f0479e1022fb
--- /dev/null
+++ b/xen/common/emul/vuart/ns16x50.c
@@ -0,0 +1,362 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * NS16550-compatible UART Emulator.
+ *
+ * See:
+ * - Serial and UART Tutorial:
+ *
https://download.freebsd.org/doc/en/articles/serial-uart/serial-uart_en.pdf
+ * - UART w/ 16 byte FIFO:
+ * https://www.ti.com/lit/ds/symlink/tl16c550c.pdf
+ * - UART w/ 64 byte FIFO:
+ * https://www.ti.com/lit/ds/symlink/tl16c750.pdf
+ *
+ * Limitations:
+ * - Only x86;
+ * - Only Xen console as a backend, no inter-domain communication (similar to
+ * vpl011 on Arm);
+ * - Only 8n1 emulation (8-bit data, no parity, 1 stop bit);
+ * - No baud rate emulation (reports 115200 baud to the guest OS);
+ * - No FIFO-less mode emulation;
+ * - No RX FIFO interrupt moderation (FCR) emulation;
+ * - No integration w/ VM snapshotting (HVM_REGISTER_SAVE_RESTORE() and
+ * friends);
+ * - No ISA IRQ sharing allowed;
+ * - No MMIO-based UART emulation.
+ */
+
+#define pr_prefix "ns16x50"
+#define pr_fmt(fmt) pr_prefix ": " fmt
+
+#ifdef CONFIG_VUART_NS16X50_DEBUG
+#define guest_prefix "FROM GUEST "
+#define ns16x50_log_level 2
+#else
+#define guest_prefix ""
+#define ns16x50_log_level 0
+#endif
+
+#include <xen/8250-uart.h>
+#include <xen/console.h>
+#include <xen/err.h>
+#include <xen/iocap.h>
+#include <xen/vuart.h>
+#include <xen/xvmalloc.h>
+
+#include <public/io/console.h>
+
+#define ns16x50_log(n, lvl, vdev, fmt, args...) do { \
+ if ( ns16x50_log_level >= n) \
+ gprintk(lvl, pr_fmt("%s: " fmt), (vdev)->name, ## args); \
+} while (0)
+
+#define ns16x50_err(vdev, fmt, args...) \
+ ns16x50_log(0, KERN_ERR, vdev, fmt, ## args)
+#define ns16x50_warn(vdev, fmt, args...) \
+ ns16x50_log(1, KERN_WARNING, vdev, fmt, ## args)
+#define ns16x50_info(vdev, fmt, args...) \
+ ns16x50_log(2, KERN_INFO, vdev, fmt, ## args)
+#define ns16x50_debug(vdev, fmt, args...) \
+ ns16x50_log(3, KERN_DEBUG, vdev, fmt, ## args)
+
+/*
+ * Number of supported registers in the UART.
+ */
+#define NS16X50_REGS_NUM (UART_SCR + 1)
+
+/*
+ * Number of emulated registers.
+ *
+ * - Emulated registers [0..NS16X50_REGS_NUM] are R/W registers for DLAB=0.
+ * - DLAB=1, R/W, DLL = NS16X50_REGS_NUM + 0
+ * - DLAB=1, R/W, DLM = NS16X50_REGS_NUM + 1
+ * - R/O, IIR (IIR_THR) = NS16X50_REGS_NUM + 2
+ */
+#define NS16X50_EMU_REGS_NUM (NS16X50_REGS_NUM + 3)
+
+/*
+ * Virtual ns16x50 device state.
+ */
+struct vuart_ns16x50 {
+ struct xencons_interface cons; /* Emulated RX/TX FIFOs */
+ uint8_t regs[NS16X50_EMU_REGS_NUM]; /* Emulated registers */
+ const char *name; /* Device name */
+ struct domain *owner; /* Owner domain */
+ const struct vuart_info *info; /* UART description */
+ spinlock_t lock; /* Protection */
+};
+
+/*
+ * Emulate 8-bit write access to ns16x50 register.
+ */
+static int ns16x50_io_write8(
+ struct vuart_ns16x50 *vdev, uint32_t reg, uint8_t *data)
+{
+ int rc = 0;
+
+ return rc;
+}
+
+/*
+ * Emulate 16-bit write access to ns16x50 register.
+ * NB: some guest OSes use outw() to access UART_DLL.
+ */
+static int ns16x50_io_write16(
+ struct vuart_ns16x50 *vdev, uint32_t reg, uint16_t *data)
+{
+ int rc = -EINVAL;
+
+ return rc;
+}
+
+/*
+ * Emulate write access to ns16x50 register.
+ */
+static int ns16x50_io_write(
+ struct vuart_ns16x50 *vdev, uint8_t reg, uint32_t size, uint32_t *data)
+{
+ int rc;
+
+ switch ( size )
+ {
+ case 1:
+ rc = ns16x50_io_write8(vdev, reg, (uint8_t *)data);
+ break;
+
+ case 2:
+ rc = ns16x50_io_write16(vdev, reg, (uint16_t *)data);
+ break;
+
+ default:
+ rc = -EINVAL;
+ break;
+ }
+
+ return rc;
+}
+
+/*
+ * Emulate 8-bit read access to ns16x50 register.
+ */
+static int ns16x50_io_read8(
+ struct vuart_ns16x50 *vdev, uint32_t reg, uint8_t *data)
+{
+ uint8_t val = 0xff;
+ int rc = 0;
+
+ *data = val;
+
+ return rc;
+}
+
+/*
+ * Emulate 16-bit read access to ns16x50 register.
+ */
+static int ns16x50_io_read16(
+ struct vuart_ns16x50 *vdev, uint32_t reg, uint16_t *data)
+{
+ uint16_t val = 0xffff;
+ int rc = -EINVAL;
+
+ *data = val;
+
+ return rc;
+}
+
+/*
+ * Emulate read access to ns16x50 register.
+ */
+static int ns16x50_io_read(
+ struct vuart_ns16x50 *vdev, uint8_t reg, uint32_t size, uint32_t *data)
+{
+ int rc;
+
+ switch ( size )
+ {
+ case 1:
+ rc = ns16x50_io_read8(vdev, reg, (uint8_t *)data);
+ break;
+
+ case 2:
+ rc = ns16x50_io_read16(vdev, reg, (uint16_t *)data);
+ break;
+
+ default:
+ *data = 0xffffffff;
+ rc = -EINVAL;
+ break;
+ }
+
+ return rc;
+}
+
+/*
+ * Emulate I/O access to ns16x50 register.
+ * Note, emulation always returns X86EMUL_OKAY, once I/O port trap is enabled.
+ */
+static int cf_check ns16x50_io_handle(
+ int dir, unsigned int addr, unsigned int size, uint32_t *data)
+{
+#define op(dir) (((dir) == IOREQ_WRITE) ? 'W' : 'R')
+ struct domain *d = rcu_lock_current_domain();
+ struct vuart *vuart = vuart_find_by_io_range(d, addr, size);
+ struct vuart_ns16x50 *vdev;
+ const struct domain *owner;
+ const struct vuart_info *info;
+ uint32_t reg;
+ unsigned dlab;
+ int rc;
+
+ if ( !vuart || !vuart->vdev )
+ {
+ printk(KERN_ERR "%c io 0x%04x %d: not initialized\n",
+ op(dir), addr, size);
+
+ ASSERT_UNREACHABLE();
+ goto out;
+ }
+ vdev = vuart->vdev;
+
+ owner = vuart->owner;
+ ASSERT(owner);
+ if ( d != owner )
+ {
+ ns16x50_err(vdev, "%c io 0x%04x %d: does not match current domain
%pv\n",
+ op(dir), addr, size, d);
+
+ ASSERT_UNREACHABLE();
+ goto out;
+ }
+
+ info = vuart->info;
+ ASSERT(info);
+ reg = addr - info->base_addr;
+ if ( !IS_ALIGNED(reg, size) )
+ {
+ ns16x50_err(vdev, "%c 0x%04x %d: unaligned access\n",
+ op(dir), addr, size);
+ goto out;
+ }
+
+ dlab = 0;
+ if ( reg >= NS16X50_REGS_NUM )
+ {
+ ns16x50_err(vdev, "%c io 0x%04x %d: DLAB=%d %02"PRIx32" 0x%08"PRIx32":
not implemented\n",
+ op(dir), addr, size, dlab, reg, *data);
+ goto out;
+ }
+
+ spin_lock(&vdev->lock);
+
+ if ( dir == IOREQ_WRITE )
+ {
+ ns16x50_debug(vdev, "%c 0x%04x %d: DLAB=%d %02"PRIx32"
0x%08"PRIx32"\n",
+ op(dir), addr, size, dlab, reg, *data);
+ rc = ns16x50_io_write(vdev, reg, size, data);
+ }
+ else
+ {
+ rc = ns16x50_io_read(vdev, reg, size, data);
+ ns16x50_debug(vdev, "%c 0x%04x %d: DLAB=%d %02"PRIx32"
0x%08"PRIx32"\n",
+ op(dir), addr, size, dlab, reg, *data);
+ }
+ if ( rc < 0 )
+ ns16x50_err(vdev, "%c 0x%04x %d: DLAB=%d %02"PRIx32" 0x%08"PRIx32":
unsupported access\n",
+ op(dir), addr, size, dlab, reg, *data);
+
+ spin_unlock(&vdev->lock);
+
+out:
+ rcu_unlock_domain(d);
+
+ return X86EMUL_OKAY;
+#undef op
+}
+
+static int ns16x50_init(void *arg)
+{
+ struct vuart_ns16x50 *vdev = arg;
+ const struct vuart_info *info = vdev->info;
+ struct domain *d = vdev->owner;
+
+ ASSERT(vdev);
+
+ register_portio_handler(d, info->base_addr, info->size, ns16x50_io_handle);
+
+ return 0;
+}
+
+static void cf_check ns16x50_deinit(void *arg)
+{
+ struct vuart_ns16x50 *vdev = arg;
+
+ ASSERT(vdev);
+}
+
+static void * cf_check ns16x50_alloc(struct domain *d, const struct vuart_info
*info)
+{
+ struct vuart_ns16x50 *vdev;
+ int rc;
+
+ if ( !info )
+ return ERR_PTR(-EINVAL);
+
+ if ( vuart_find_by_io_range(d, info->base_addr, info->size) )
+ {
+ ns16x50_err(info, "already registered\n");
+ return ERR_PTR(-EBUSY);
+ }
+
+ if ( !is_hvm_domain(d) )
+ {
+ ns16x50_err(info, "not an HVM domain\n");
+ return ERR_PTR(-ENOSYS);
+ }
+
+ vdev = xvzalloc(typeof(*vdev));
+ if ( !vdev )
+ {
+ ns16x50_err(info, "failed to allocate memory\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* Save convenience pointer. */
+ vdev->name = info->name;
+ vdev->owner = d;
+ vdev->info = info;
+
+ rc = ns16x50_init(vdev);
+ if ( rc )
+ return ERR_PTR(rc);
+
+ return vdev;
+}
+
+static void cf_check ns16x50_free(void *arg)
+{
+ struct vuart_ns16x50 *vdev = arg;
+
+ if ( vdev )
+ ns16x50_deinit(vdev);
+
+ XVFREE(vdev);
+}
+
+#define ns16x50_emulator \
+{ \
+ .compatible = "ns16550", \
+ .alloc = ns16x50_alloc, \
+ .free = ns16x50_free, \
+ .dump_state = NULL, \
+ .put_rx = NULL, \
+}
+
+VUART_REGISTER(ns16x50, ns16x50_emulator);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 02bdc256ce37..613f4596e33d 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -23,6 +23,7 @@
#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>
@@ -660,6 +661,9 @@ struct domain
struct {
/* Permission to take ownership of the physical console input. */
bool input_allowed;
+#ifdef CONFIG_VUART_FRAMEWORK
+ struct vuart *vuart;
+#endif
} console;
} __aligned(PAGE_SIZE);
--
2.51.0
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |