Re: [PATCH v5 2/3] xen/console: introduce console_send()
On Mon, 19 May 2025, dm...@proton.me wrote:
> From: Denis Mukhin
>
> guest_console_write() duplicates the code from __putstr(), eliminate code
> duplication.
>
> Introduce console_send() for sending a message on console devices.
>
> Also, introduce internal console flags to control which console devices
> should be used.
>
> No functional change intended.
>
> Signed-off-by: Denis Mukhin
Reviewed-by: Stefano Stabellini
> ---
> Changes since v4:
> - fixup for console_send(): do CONSOLE_RING_VIRQ flag processing under
> CONSOLE_RING
> ---
> xen/drivers/char/console.c | 133 +++--
> 1 file changed, 84 insertions(+), 49 deletions(-)
>
> diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
> index b4757844e6..0c0cc6677c 100644
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -41,6 +41,28 @@
> #include
> #endif
>
> +/* Internal console flags. */
> +enum {
> +CONSOLE_SERIAL = BIT(0, U),/* Use serial device. */
> +CONSOLE_PV = BIT(1, U),/* Use PV console. */
> +CONSOLE_VIDEO = BIT(2, U),/* Use video device. */
> +CONSOLE_DEBUG = BIT(3, U),/* Use debug device. */
> +CONSOLE_RING= BIT(4, U),/* Use console ring. */
> +CONSOLE_RING_VIRQ = BIT(5, U),/* Use console ring VIRQ. */
> +
> +/* Default console flags. */
> +CONSOLE_DEFAULT = CONSOLE_SERIAL |
> + CONSOLE_PV |
> + CONSOLE_VIDEO |
> + CONSOLE_RING_VIRQ |
> + CONSOLE_DEBUG,
> +
> +/* Use all known console devices. */
> +CONSOLE_ALL = CONSOLE_DEFAULT | CONSOLE_RING,
> +};
> +
> +static void console_send(const char *str, size_t len, unsigned int flags);
> +
> /* console: comma-separated list of console outputs. */
> static char __initdata opt_console[30] = OPT_CONSOLE_STR;
> string_param("console", opt_console);
> @@ -428,9 +450,6 @@ void console_serial_puts(const char *s, size_t nr)
> serial_steal_fn(s, nr);
> else
> serial_puts(sercon_handle, s, nr);
> -
> -/* Copy all serial output into PV console */
> -pv_console_puts(s, nr);
> }
>
> static void cf_check dump_console_ring_key(unsigned char key)
> @@ -464,8 +483,7 @@ static void cf_check dump_console_ring_key(unsigned char
> key)
> c += len;
> }
>
> -console_serial_puts(buf, sofar);
> -video_puts(buf, sofar);
> +console_send(buf, sofar, CONSOLE_SERIAL | CONSOLE_VIDEO | CONSOLE_PV);
>
> free_xenheap_pages(buf, order);
> }
> @@ -614,11 +632,71 @@ static inline void xen_console_write_debug_port(const
> char *buf, size_t len)
> }
> #endif
>
> +static inline void console_debug_puts(const char *str, size_t len)
> +{
> +#ifdef CONFIG_X86
> +if ( opt_console_xen )
> +{
> +if ( xen_guest )
> +xen_hypercall_console_write(str, len);
> +else
> +xen_console_write_debug_port(str, len);
> +}
> +#endif
> +}
> +
> +/*
> + * Send a message on console device(s).
> + *
> + * That will handle all possible scenarios working w/ console
> + * - physical console (serial console, VGA console (x86 only));
> + * - PV console;
> + * - debug console (x86 only): debug I/O port or __HYPERVISOR_console_io
> + * hypercall;
> + * - console ring.
> + */
> +static void console_send(const char *str, size_t len, unsigned int flags)
> +{
> +if ( flags & CONSOLE_SERIAL )
> +console_serial_puts(str, len);
> +
> +if ( flags & CONSOLE_PV )
> +pv_console_puts(str, len);
> +
> +if ( flags & CONSOLE_VIDEO )
> +video_puts(str, len);
> +
> +if ( flags & CONSOLE_DEBUG )
> +console_debug_puts(str, len);
> +
> +if ( flags & CONSOLE_RING )
> +{
> +conring_puts(str, len);
> +
> +if ( flags & CONSOLE_RING_VIRQ )
> +tasklet_schedule(&conring_tasklet);
> +}
> +}
> +
> +static inline void __putstr(const char *str)
> +{
> +unsigned int flags = CONSOLE_ALL;
> +
> +ASSERT(rspin_is_locked(&console_lock));
> +
> +if ( conring_no_notify )
> +flags &= ~CONSOLE_RING_VIRQ;
> +
> +console_send(str, strlen(str), flags);
> +}
> +
> static long guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
> unsigned int count)
> {
> char kbuf[128];
> unsigned int kcount = 0;
> +unsigned int flags = opt_console_to_ring
> + ? CONSOLE_ALL : CONSOLE_DEFAULT;
> struct domain *cd = current->domain;
>
> while ( count > 0 )
> @@ -636,26 +714,7 @@ static long
> guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
> {
> /* Use direct console output as it could be interactive */
> nrspin_lock_irq(&console_lock);
> -
> -console_serial_puts(kbuf, kcount);
> -video_pu
[PATCH v5 2/3] xen/console: introduce console_send()
From: Denis Mukhin
guest_console_write() duplicates the code from __putstr(), eliminate code
duplication.
Introduce console_send() for sending a message on console devices.
Also, introduce internal console flags to control which console devices
should be used.
No functional change intended.
Signed-off-by: Denis Mukhin
---
Changes since v4:
- fixup for console_send(): do CONSOLE_RING_VIRQ flag processing under
CONSOLE_RING
---
xen/drivers/char/console.c | 133 +++--
1 file changed, 84 insertions(+), 49 deletions(-)
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index b4757844e6..0c0cc6677c 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -41,6 +41,28 @@
#include
#endif
+/* Internal console flags. */
+enum {
+CONSOLE_SERIAL = BIT(0, U),/* Use serial device. */
+CONSOLE_PV = BIT(1, U),/* Use PV console. */
+CONSOLE_VIDEO = BIT(2, U),/* Use video device. */
+CONSOLE_DEBUG = BIT(3, U),/* Use debug device. */
+CONSOLE_RING= BIT(4, U),/* Use console ring. */
+CONSOLE_RING_VIRQ = BIT(5, U),/* Use console ring VIRQ. */
+
+/* Default console flags. */
+CONSOLE_DEFAULT = CONSOLE_SERIAL |
+ CONSOLE_PV |
+ CONSOLE_VIDEO |
+ CONSOLE_RING_VIRQ |
+ CONSOLE_DEBUG,
+
+/* Use all known console devices. */
+CONSOLE_ALL = CONSOLE_DEFAULT | CONSOLE_RING,
+};
+
+static void console_send(const char *str, size_t len, unsigned int flags);
+
/* console: comma-separated list of console outputs. */
static char __initdata opt_console[30] = OPT_CONSOLE_STR;
string_param("console", opt_console);
@@ -428,9 +450,6 @@ void console_serial_puts(const char *s, size_t nr)
serial_steal_fn(s, nr);
else
serial_puts(sercon_handle, s, nr);
-
-/* Copy all serial output into PV console */
-pv_console_puts(s, nr);
}
static void cf_check dump_console_ring_key(unsigned char key)
@@ -464,8 +483,7 @@ static void cf_check dump_console_ring_key(unsigned char
key)
c += len;
}
-console_serial_puts(buf, sofar);
-video_puts(buf, sofar);
+console_send(buf, sofar, CONSOLE_SERIAL | CONSOLE_VIDEO | CONSOLE_PV);
free_xenheap_pages(buf, order);
}
@@ -614,11 +632,71 @@ static inline void xen_console_write_debug_port(const
char *buf, size_t len)
}
#endif
+static inline void console_debug_puts(const char *str, size_t len)
+{
+#ifdef CONFIG_X86
+if ( opt_console_xen )
+{
+if ( xen_guest )
+xen_hypercall_console_write(str, len);
+else
+xen_console_write_debug_port(str, len);
+}
+#endif
+}
+
+/*
+ * Send a message on console device(s).
+ *
+ * That will handle all possible scenarios working w/ console
+ * - physical console (serial console, VGA console (x86 only));
+ * - PV console;
+ * - debug console (x86 only): debug I/O port or __HYPERVISOR_console_io
+ * hypercall;
+ * - console ring.
+ */
+static void console_send(const char *str, size_t len, unsigned int flags)
+{
+if ( flags & CONSOLE_SERIAL )
+console_serial_puts(str, len);
+
+if ( flags & CONSOLE_PV )
+pv_console_puts(str, len);
+
+if ( flags & CONSOLE_VIDEO )
+video_puts(str, len);
+
+if ( flags & CONSOLE_DEBUG )
+console_debug_puts(str, len);
+
+if ( flags & CONSOLE_RING )
+{
+conring_puts(str, len);
+
+if ( flags & CONSOLE_RING_VIRQ )
+tasklet_schedule(&conring_tasklet);
+}
+}
+
+static inline void __putstr(const char *str)
+{
+unsigned int flags = CONSOLE_ALL;
+
+ASSERT(rspin_is_locked(&console_lock));
+
+if ( conring_no_notify )
+flags &= ~CONSOLE_RING_VIRQ;
+
+console_send(str, strlen(str), flags);
+}
+
static long guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
unsigned int count)
{
char kbuf[128];
unsigned int kcount = 0;
+unsigned int flags = opt_console_to_ring
+ ? CONSOLE_ALL : CONSOLE_DEFAULT;
struct domain *cd = current->domain;
while ( count > 0 )
@@ -636,26 +714,7 @@ static long
guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
{
/* Use direct console output as it could be interactive */
nrspin_lock_irq(&console_lock);
-
-console_serial_puts(kbuf, kcount);
-video_puts(kbuf, kcount);
-
-#ifdef CONFIG_X86
-if ( opt_console_xen )
-{
-if ( xen_guest )
-xen_hypercall_console_write(kbuf, kcount);
-else
-xen_console_write_debug_port(kbuf, kcount);
-}
-#endif
-
-if ( opt_console_to_ring )
-{
-conring_puts(kbuf, k
