* [PATCH v3 1/5] xen/console: rename switch_serial_input() to console_switch_input()
2025-05-19 20:12 [PATCH v3 0/5] xen/console: cleanup console input switch logic dmkhn
@ 2025-05-19 20:12 ` dmkhn
2025-05-20 6:07 ` Jan Beulich
2025-05-19 20:12 ` [PATCH v3 2/5] xen/console: introduce console_get_domid() dmkhn
` (3 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: dmkhn @ 2025-05-19 20:12 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
Update the function name as per naming notation in the console driver.
No functional change.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v2:
- rebased
- Link to v2: https://lore.kernel.org/xen-devel/20250331230508.440198-5-dmukhin@ford.com/
---
xen/drivers/char/console.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index c3150fbdb7..c8dde38376 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -487,7 +487,7 @@ void console_put_domain(struct domain *d)
rcu_unlock_domain(d);
}
-static void switch_serial_input(void)
+static void console_switch_input(void)
{
unsigned int next_rx = console_rx;
@@ -581,7 +581,7 @@ static void cf_check serial_rx(char c)
/* We eat CTRL-<switch_char> in groups of 3 to switch console input. */
if ( ++switch_code_count == 3 )
{
- switch_serial_input();
+ console_switch_input();
switch_code_count = 0;
}
return;
@@ -1125,7 +1125,7 @@ void __init console_endboot(void)
"toggle host/guest log level adjustment", 0);
/* Serial input is directed to DOM0 by default. */
- switch_serial_input();
+ console_switch_input();
}
int __init console_has(const char *device)
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v3 2/5] xen/console: introduce console_get_domid()
2025-05-19 20:12 [PATCH v3 0/5] xen/console: cleanup console input switch logic dmkhn
2025-05-19 20:12 ` [PATCH v3 1/5] xen/console: rename switch_serial_input() to console_switch_input() dmkhn
@ 2025-05-19 20:12 ` dmkhn
2025-05-20 6:20 ` Jan Beulich
2025-05-19 20:12 ` [PATCH v3 3/5] xen/console: introduce console input permission dmkhn
` (2 subsequent siblings)
4 siblings, 1 reply; 10+ messages in thread
From: dmkhn @ 2025-05-19 20:12 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
Add console_get_domid() to the console driver to retrieve the current console
owner domain ID.
Use the function in vpl011 emulator which leads to simpler code.
Make console_{get,put}_domain() private to the console driver.
No functional change intended.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v2:
- changed commit subject line
- Link to v2: https://lore.kernel.org/xen-devel/20250331230508.440198-8-dmukhin@ford.com/
---
xen/arch/arm/vpl011.c | 5 +----
xen/drivers/char/console.c | 11 +++++++++--
xen/include/xen/console.h | 3 +--
3 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
index 66047bf33c..0f58b2c900 100644
--- a/xen/arch/arm/vpl011.c
+++ b/xen/arch/arm/vpl011.c
@@ -78,12 +78,11 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
unsigned long flags;
struct vpl011 *vpl011 = &d->arch.vpl011;
struct vpl011_xen_backend *intf = vpl011->backend.xen;
- struct domain *input = console_get_domain();
VPL011_LOCK(d, flags);
intf->out[intf->out_prod++] = data;
- if ( d == input )
+ if ( d->domain_id == console_get_domid() )
{
if ( intf->out_prod == 1 )
{
@@ -123,8 +122,6 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
vpl011_update_interrupt_status(d);
VPL011_UNLOCK(d, flags);
-
- console_put_domain(input);
}
/*
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index c8dde38376..86fd0b427d 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -474,19 +474,26 @@ static unsigned int __read_mostly console_rx = 0;
#define max_console_rx (max_init_domid + 1)
-struct domain *console_get_domain(void)
+static struct domain *console_get_domain(void)
{
if ( console_rx == 0 )
return NULL;
return rcu_lock_domain_by_id(console_rx - 1);
}
-void console_put_domain(struct domain *d)
+static void console_put_domain(struct domain *d)
{
if ( d )
rcu_unlock_domain(d);
}
+domid_t console_get_domid(void)
+{
+ if ( console_rx == 0 )
+ return DOMID_XEN;
+ return console_rx - 1;
+}
+
static void console_switch_input(void)
{
unsigned int next_rx = console_rx;
diff --git a/xen/include/xen/console.h b/xen/include/xen/console.h
index 83cbc9fbda..c6f9d84d80 100644
--- a/xen/include/xen/console.h
+++ b/xen/include/xen/console.h
@@ -32,8 +32,7 @@ void console_end_sync(void);
void console_start_log_everything(void);
void console_end_log_everything(void);
-struct domain *console_get_domain(void);
-void console_put_domain(struct domain *d);
+domid_t console_get_domid(void);
/*
* Steal output from the console. Returns +ve identifier, else -ve error.
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v3 2/5] xen/console: introduce console_get_domid()
2025-05-19 20:12 ` [PATCH v3 2/5] xen/console: introduce console_get_domid() dmkhn
@ 2025-05-20 6:20 ` Jan Beulich
2025-05-22 0:30 ` dmkhn
0 siblings, 1 reply; 10+ messages in thread
From: Jan Beulich @ 2025-05-20 6:20 UTC (permalink / raw)
To: dmkhn
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, xen-devel
On 19.05.2025 22:12, dmkhn@proton.me wrote:
> --- a/xen/arch/arm/vpl011.c
> +++ b/xen/arch/arm/vpl011.c
> @@ -78,12 +78,11 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
> unsigned long flags;
> struct vpl011 *vpl011 = &d->arch.vpl011;
> struct vpl011_xen_backend *intf = vpl011->backend.xen;
> - struct domain *input = console_get_domain();
>
> VPL011_LOCK(d, flags);
>
> intf->out[intf->out_prod++] = data;
> - if ( d == input )
> + if ( d->domain_id == console_get_domid() )
How do you know d isn't a domain different from the one that was the
console "owner" prior to being destroyed? Original code guaranteed this
up to ...
> @@ -123,8 +122,6 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
> vpl011_update_interrupt_status(d);
>
> VPL011_UNLOCK(d, flags);
> -
> - console_put_domain(input);
... here.
Jan
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v3 2/5] xen/console: introduce console_get_domid()
2025-05-20 6:20 ` Jan Beulich
@ 2025-05-22 0:30 ` dmkhn
0 siblings, 0 replies; 10+ messages in thread
From: dmkhn @ 2025-05-22 0:30 UTC (permalink / raw)
To: Jan Beulich
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, xen-devel
On Tue, May 20, 2025 at 08:20:16AM +0200, Jan Beulich wrote:
> On 19.05.2025 22:12, dmkhn@proton.me wrote:
> > --- a/xen/arch/arm/vpl011.c
> > +++ b/xen/arch/arm/vpl011.c
> > @@ -78,12 +78,11 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
> > unsigned long flags;
> > struct vpl011 *vpl011 = &d->arch.vpl011;
> > struct vpl011_xen_backend *intf = vpl011->backend.xen;
> > - struct domain *input = console_get_domain();
> >
> > VPL011_LOCK(d, flags);
> >
> > intf->out[intf->out_prod++] = data;
> > - if ( d == input )
> > + if ( d->domain_id == console_get_domid() )
>
> How do you know d isn't a domain different from the one that was the
> console "owner" prior to being destroyed? Original code guaranteed this
> up to ...
>
> > @@ -123,8 +122,6 @@ static void vpl011_write_data_xen(struct domain *d, uint8_t data)
> > vpl011_update_interrupt_status(d);
> >
> > VPL011_UNLOCK(d, flags);
> > -
> > - console_put_domain(input);
>
> ... here.
Agreed; I will drop the code change in the next iteration.
Thanks.
>
> Jan
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3 3/5] xen/console: introduce console input permission
2025-05-19 20:12 [PATCH v3 0/5] xen/console: cleanup console input switch logic dmkhn
2025-05-19 20:12 ` [PATCH v3 1/5] xen/console: rename switch_serial_input() to console_switch_input() dmkhn
2025-05-19 20:12 ` [PATCH v3 2/5] xen/console: introduce console_get_domid() dmkhn
@ 2025-05-19 20:12 ` dmkhn
2025-05-19 20:12 ` [PATCH v3 4/5] xen/console: remove max_init_domid dependency dmkhn
2025-05-19 20:12 ` [PATCH v3 5/5] xen/console: rename console_rx to console_domid dmkhn
4 siblings, 0 replies; 10+ messages in thread
From: dmkhn @ 2025-05-19 20:12 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
Add new flag to domain structure for marking permission to intercept
the physical console input by the domain.
Update console input switch logic accordingly.
No functional change intended.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v2:
- rebased
- Link to v2: https://lore.kernel.org/xen-devel/20250331230508.440198-2-dmukhin@ford.com/
---
xen/arch/arm/vpl011.c | 2 ++
xen/arch/x86/pv/shim.c | 2 ++
xen/common/domain.c | 2 ++
xen/drivers/char/console.c | 18 +++++++++++++++++-
xen/include/xen/sched.h | 8 +++++++-
5 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
index 0f58b2c900..d0e5504e9e 100644
--- a/xen/arch/arm/vpl011.c
+++ b/xen/arch/arm/vpl011.c
@@ -734,6 +734,8 @@ int domain_vpl011_init(struct domain *d, struct vpl011_init_info *info)
register_mmio_handler(d, &vpl011_mmio_handler,
vpl011->base_addr, GUEST_PL011_SIZE, NULL);
+ d->console.input_allowed = true;
+
return 0;
out1:
diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
index c506cc0bec..bc2a7dd5fa 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -238,6 +238,8 @@ void __init pv_shim_setup_dom(struct domain *d, l4_pgentry_t *l4start,
* guest from depleting the shim memory pool.
*/
d->max_pages = domain_tot_pages(d);
+
+ d->console.input_allowed = true;
}
static void write_start_info(struct domain *d)
diff --git a/xen/common/domain.c b/xen/common/domain.c
index cb05156ff5..6a6cdd991b 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -836,6 +836,8 @@ struct domain *domain_create(domid_t domid,
flags |= CDF_hardware;
if ( old_hwdom )
old_hwdom->cdf &= ~CDF_hardware;
+
+ d->console.input_allowed = true;
}
/* Holding CDF_* internal flags. */
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 86fd0b427d..ccecda6523 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -476,9 +476,21 @@ static unsigned int __read_mostly console_rx = 0;
static struct domain *console_get_domain(void)
{
+ struct domain *d;
+
if ( console_rx == 0 )
return NULL;
- return rcu_lock_domain_by_id(console_rx - 1);
+
+ d = rcu_lock_domain_by_id(console_rx - 1);
+ if ( !d )
+ return NULL;
+
+ if ( d->console.input_allowed )
+ return d;
+
+ rcu_unlock_domain(d);
+
+ return NULL;
}
static void console_put_domain(struct domain *d)
@@ -522,6 +534,10 @@ static void console_switch_input(void)
if ( d )
{
rcu_unlock_domain(d);
+
+ if ( !d->console.input_allowed )
+ break;
+
console_rx = next_rx;
printk("*** Serial input to DOM%u", domid);
break;
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 559d201e0c..e91c99a8f3 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -512,7 +512,7 @@ struct domain
bool auto_node_affinity;
/* Is this guest fully privileged (aka dom0)? */
bool is_privileged;
- /* Can this guest access the Xen console? */
+ /* XSM: permission to use HYPERCALL_console_io hypercall */
bool is_console;
/* Is this guest being debugged by dom0? */
bool debugger_attached;
@@ -651,6 +651,12 @@ struct domain
unsigned int num_llc_colors;
const unsigned int *llc_colors;
#endif
+
+ /* Console settings. */
+ struct {
+ /* Permission to take ownership of the physical console input. */
+ bool input_allowed;
+ } console;
} __aligned(PAGE_SIZE);
static inline struct page_list_head *page_to_list(
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* [PATCH v3 4/5] xen/console: remove max_init_domid dependency
2025-05-19 20:12 [PATCH v3 0/5] xen/console: cleanup console input switch logic dmkhn
` (2 preceding siblings ...)
2025-05-19 20:12 ` [PATCH v3 3/5] xen/console: introduce console input permission dmkhn
@ 2025-05-19 20:12 ` dmkhn
2025-05-20 6:28 ` Jan Beulich
2025-05-19 20:12 ` [PATCH v3 5/5] xen/console: rename console_rx to console_domid dmkhn
4 siblings, 1 reply; 10+ messages in thread
From: dmkhn @ 2025-05-19 20:12 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
The physical console input rotation depends on max_init_domid symbol, which is
managed differently across architectures.
Instead of trying to manage max_init_domid in the arch-common code the console
input rotation code can be reworked by removing dependency on max_init_domid
entirely.
To do that, introduce domid_find_with_input_allowed() in arch-independent
location to find the ID of the next possible console owner domain. The IDs
are rotated across non-system domain IDs and DOMID_XEN.
Also, introduce helper console_set_domid() for updating identifier of the
current console input owner (points to Xen or domain).
Use domid_find_with_input_allowed() and console_set_domid() in
console_switch_input().
Remove uses of max_init_domid in the code.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v2:
- reworked to traversing domain list directly
- Link to v2: https://lore.kernel.org/xen-devel/20250331230508.440198-7-dmukhin@ford.com/
---
xen/arch/arm/include/asm/setup.h | 2 -
xen/arch/arm/setup.c | 2 -
xen/arch/ppc/include/asm/setup.h | 2 -
xen/arch/riscv/include/asm/setup.h | 2 -
xen/arch/x86/include/asm/setup.h | 2 -
xen/common/device-tree/dom0less-build.c | 2 -
xen/common/domain.c | 29 +++++++
xen/drivers/char/console.c | 102 +++++++++---------------
xen/include/xen/domain.h | 1 +
9 files changed, 66 insertions(+), 78 deletions(-)
diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index 6cf272c160..f107e8eebb 100644
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -25,8 +25,6 @@ struct map_range_data
struct rangeset *irq_ranges;
};
-extern domid_t max_init_domid;
-
void copy_from_paddr(void *dst, paddr_t paddr, unsigned long len);
size_t estimate_efi_size(unsigned int mem_nr_banks);
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 10b46d0684..53e2f8b537 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -61,8 +61,6 @@ struct cpuinfo_arm __read_mostly system_cpuinfo;
bool __read_mostly acpi_disabled;
#endif
-domid_t __read_mostly max_init_domid;
-
static __used void init_done(void)
{
int rc;
diff --git a/xen/arch/ppc/include/asm/setup.h b/xen/arch/ppc/include/asm/setup.h
index e4f64879b6..956fa6985a 100644
--- a/xen/arch/ppc/include/asm/setup.h
+++ b/xen/arch/ppc/include/asm/setup.h
@@ -1,6 +1,4 @@
#ifndef __ASM_PPC_SETUP_H__
#define __ASM_PPC_SETUP_H__
-#define max_init_domid (0)
-
#endif /* __ASM_PPC_SETUP_H__ */
diff --git a/xen/arch/riscv/include/asm/setup.h b/xen/arch/riscv/include/asm/setup.h
index c9d69cdf51..d1fc64b673 100644
--- a/xen/arch/riscv/include/asm/setup.h
+++ b/xen/arch/riscv/include/asm/setup.h
@@ -5,8 +5,6 @@
#include <xen/types.h>
-#define max_init_domid (0)
-
void setup_mm(void);
void copy_from_paddr(void *dst, paddr_t paddr, unsigned long len);
diff --git a/xen/arch/x86/include/asm/setup.h b/xen/arch/x86/include/asm/setup.h
index ac34c69855..b67de8577f 100644
--- a/xen/arch/x86/include/asm/setup.h
+++ b/xen/arch/x86/include/asm/setup.h
@@ -69,6 +69,4 @@ extern bool opt_dom0_verbose;
extern bool opt_dom0_cpuid_faulting;
extern bool opt_dom0_msr_relaxed;
-#define max_init_domid (0)
-
#endif
diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tree/dom0less-build.c
index 8e38affd0c..4c050b9ded 100644
--- a/xen/common/device-tree/dom0less-build.c
+++ b/xen/common/device-tree/dom0less-build.c
@@ -977,8 +977,6 @@ void __init create_domUs(void)
domid = domid_alloc(DOMID_INVALID);
if ( domid == DOMID_INVALID )
panic("Error allocating ID for domain %s\n", dt_node_name(node));
- if ( max_init_domid < domid )
- max_init_domid = domid;
d = domain_create(domid, &d_cfg, flags);
if ( IS_ERR(d) )
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6a6cdd991b..90bd42b633 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -2460,6 +2460,35 @@ void domid_free(domid_t domid)
spin_unlock(&domid_lock);
}
+/*
+ * Find the ID of the next possible console owner domain.
+ *
+ * @return Domain ID: DOMID_XEN or non-system domain IDs within
+ * the range of [0..CONFIG_MAX_DOMID-1].
+ */
+domid_t domid_find_with_input_allowed(domid_t hint)
+{
+ struct domain *d;
+ domid_t domid = DOMID_XEN;
+
+ spin_lock(&domlist_update_lock);
+
+ for ( d = domid_to_domain(hint);
+ d && likely(get_domain(d)) && (d->domain_id < CONFIG_MAX_DOMID);
+ d = d->next_in_list )
+ {
+ if ( d->console.input_allowed )
+ {
+ domid = d->domain_id;
+ break;
+ }
+ }
+
+ spin_unlock(&domlist_update_lock);
+
+ return domid;
+}
+
/*
* Local variables:
* mode: C
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index ccecda6523..ff20706ac9 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -462,26 +462,17 @@ static void cf_check dump_console_ring_key(unsigned char key)
/*
* CTRL-<switch_char> changes input direction, rotating among Xen, Dom0,
- * and the DomUs started from Xen at boot.
+ * and the DomUs.
*/
#define switch_code (opt_conswitch[0]-'a'+1)
-/*
- * console_rx=0 => input to xen
- * console_rx=1 => input to dom0 (or the sole shim domain)
- * console_rx=N => input to dom(N-1)
- */
-static unsigned int __read_mostly console_rx = 0;
-#define max_console_rx (max_init_domid + 1)
+/* Console owner domain identifier. */
+static domid_t __read_mostly console_rx = DOMID_XEN;
static struct domain *console_get_domain(void)
{
- struct domain *d;
+ struct domain *d = rcu_lock_domain_by_id(console_rx);
- if ( console_rx == 0 )
- return NULL;
-
- d = rcu_lock_domain_by_id(console_rx - 1);
if ( !d )
return NULL;
@@ -499,50 +490,14 @@ static void console_put_domain(struct domain *d)
rcu_unlock_domain(d);
}
-domid_t console_get_domid(void)
+static void console_set_domid(domid_t domid)
{
- if ( console_rx == 0 )
- return DOMID_XEN;
- return console_rx - 1;
-}
+ if ( domid == DOMID_XEN )
+ printk("*** Serial input to Xen");
+ else
+ printk("*** Serial input to DOM%u", domid);
-static void console_switch_input(void)
-{
- unsigned int next_rx = console_rx;
-
- /*
- * Rotate among Xen, dom0 and boot-time created domUs while skipping
- * switching serial input to non existing domains.
- */
- for ( ; ; )
- {
- domid_t domid;
- struct domain *d;
-
- if ( next_rx++ >= max_console_rx )
- {
- console_rx = 0;
- printk("*** Serial input to Xen");
- break;
- }
-
- if ( consoled_is_enabled() && next_rx == 1 )
- domid = get_initial_domain_id();
- else
- domid = next_rx - 1;
- d = rcu_lock_domain_by_id(domid);
- if ( d )
- {
- rcu_unlock_domain(d);
-
- if ( !d->console.input_allowed )
- break;
-
- console_rx = next_rx;
- printk("*** Serial input to DOM%u", domid);
- break;
- }
- }
+ console_rx = domid;
if ( switch_code )
printk(" (type 'CTRL-%c' three times to switch input)",
@@ -550,12 +505,35 @@ static void console_switch_input(void)
printk("\n");
}
+domid_t console_get_domid(void)
+{
+ return console_rx;
+}
+
+/*
+ * Switch console focus.
+ * Rotates input focus among Xen and domains with console input permission.
+ */
+static void console_switch_input(void)
+{
+ domid_t hint;
+
+ if ( console_rx == DOMID_XEN )
+ hint = get_initial_domain_id();
+ else
+ hint = console_rx + 1;
+
+ hint = domid_find_with_input_allowed(hint);
+
+ console_set_domid(hint);
+}
+
static void __serial_rx(char c)
{
struct domain *d;
int rc = 0;
- if ( console_rx == 0 )
+ if ( console_rx == DOMID_XEN )
return handle_keypress(c, false);
d = console_get_domain();
@@ -1130,14 +1108,6 @@ void __init console_endboot(void)
video_endboot();
- /*
- * If user specifies so, we fool the switch routine to redirect input
- * straight back to Xen. I use this convoluted method so we still print
- * a useful 'how to switch' message.
- */
- if ( opt_conswitch[1] == 'x' )
- console_rx = max_console_rx;
-
register_keyhandler('w', dump_console_ring_key,
"synchronously dump console ring buffer (dmesg)", 0);
register_irq_keyhandler('+', &do_inc_thresh,
@@ -1147,8 +1117,8 @@ void __init console_endboot(void)
register_irq_keyhandler('G', &do_toggle_guest,
"toggle host/guest log level adjustment", 0);
- /* Serial input is directed to DOM0 by default. */
- console_switch_input();
+ if ( opt_conswitch[1] != 'x' )
+ (void)console_set_domid(get_initial_domain_id());
}
int __init console_has(const char *device)
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 8aab05ae93..a88eb34f3f 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -36,6 +36,7 @@ void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info);
void arch_get_domain_info(const struct domain *d,
struct xen_domctl_getdomaininfo *info);
+domid_t domid_find_with_input_allowed(domid_t hint);
domid_t get_initial_domain_id(void);
domid_t domid_alloc(domid_t domid);
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [PATCH v3 4/5] xen/console: remove max_init_domid dependency
2025-05-19 20:12 ` [PATCH v3 4/5] xen/console: remove max_init_domid dependency dmkhn
@ 2025-05-20 6:28 ` Jan Beulich
0 siblings, 0 replies; 10+ messages in thread
From: Jan Beulich @ 2025-05-20 6:28 UTC (permalink / raw)
To: dmkhn
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, xen-devel
On 19.05.2025 22:12, dmkhn@proton.me wrote:
> From: Denis Mukhin <dmukhin@ford.com>
>
> The physical console input rotation depends on max_init_domid symbol, which is
> managed differently across architectures.
>
> Instead of trying to manage max_init_domid in the arch-common code the console
> input rotation code can be reworked by removing dependency on max_init_domid
> entirely.
... at the expense of doing (worst case) 32k iterations just to find nothing
(else). Iirc it was to avoid this why max_init_domid was introduced.
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -2460,6 +2460,35 @@ void domid_free(domid_t domid)
> spin_unlock(&domid_lock);
> }
>
> +/*
> + * Find the ID of the next possible console owner domain.
> + *
> + * @return Domain ID: DOMID_XEN or non-system domain IDs within
> + * the range of [0..CONFIG_MAX_DOMID-1].
> + */
> +domid_t domid_find_with_input_allowed(domid_t hint)
> +{
> + struct domain *d;
const?
> + domid_t domid = DOMID_XEN;
> +
> + spin_lock(&domlist_update_lock);
Why this heavy lock? Other functions iterating the list just use the RCU
read lock.
Jan
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3 5/5] xen/console: rename console_rx to console_domid
2025-05-19 20:12 [PATCH v3 0/5] xen/console: cleanup console input switch logic dmkhn
` (3 preceding siblings ...)
2025-05-19 20:12 ` [PATCH v3 4/5] xen/console: remove max_init_domid dependency dmkhn
@ 2025-05-19 20:12 ` dmkhn
4 siblings, 0 replies; 10+ messages in thread
From: dmkhn @ 2025-05-19 20:12 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
Update the symbol name to match the code better.
No functional change.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v2:
- new patch
---
xen/drivers/char/console.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index ff20706ac9..afcc6a236e 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -467,11 +467,11 @@ static void cf_check dump_console_ring_key(unsigned char key)
#define switch_code (opt_conswitch[0]-'a'+1)
/* Console owner domain identifier. */
-static domid_t __read_mostly console_rx = DOMID_XEN;
+static domid_t __read_mostly console_domid = DOMID_XEN;
static struct domain *console_get_domain(void)
{
- struct domain *d = rcu_lock_domain_by_id(console_rx);
+ struct domain *d = rcu_lock_domain_by_id(console_domid);
if ( !d )
return NULL;
@@ -497,7 +497,7 @@ static void console_set_domid(domid_t domid)
else
printk("*** Serial input to DOM%u", domid);
- console_rx = domid;
+ console_domid = domid;
if ( switch_code )
printk(" (type 'CTRL-%c' three times to switch input)",
@@ -507,7 +507,7 @@ static void console_set_domid(domid_t domid)
domid_t console_get_domid(void)
{
- return console_rx;
+ return console_domid;
}
/*
@@ -518,10 +518,10 @@ static void console_switch_input(void)
{
domid_t hint;
- if ( console_rx == DOMID_XEN )
+ if ( console_domid == DOMID_XEN )
hint = get_initial_domain_id();
else
- hint = console_rx + 1;
+ hint = console_domid + 1;
hint = domid_find_with_input_allowed(hint);
@@ -533,7 +533,7 @@ static void __serial_rx(char c)
struct domain *d;
int rc = 0;
- if ( console_rx == DOMID_XEN )
+ if ( console_domid == DOMID_XEN )
return handle_keypress(c, false);
d = console_get_domain();
--
2.34.1
^ permalink raw reply related [flat|nested] 10+ messages in thread