---
xen/arch/arm/asm-offsets.c | 4 ++
xen/arch/arm/domain.c | 115 ++++++++++++----------------------------
xen/arch/arm/domain_build.c | 3 +-
xen/arch/arm/entry.S | 16 ++++++
xen/arch/arm/setup.c | 3 +-
xen/include/asm-arm/current.h | 41 ++++++++------
xen/include/asm-arm/domain.h | 21 +++++++-
xen/include/asm-arm/regs.h | 4 +-
xen/include/asm-arm/system.h | 2 +
9 files changed, 104 insertions(+), 105 deletions(-)
diff --git a/xen/arch/arm/asm-offsets.c b/xen/arch/arm/asm-offsets.c
index ee5d5d4..cc1a72a 100644
--- a/xen/arch/arm/asm-offsets.c
+++ b/xen/arch/arm/asm-offsets.c
@@ -7,6 +7,7 @@
#include <xen/config.h>
#include <xen/types.h>
+#include <xen/sched.h>
#include <public/xen.h>
#include <asm/current.h>
@@ -65,7 +66,10 @@ void __dummy__(void)
BLANK();
DEFINE(CPUINFO_sizeof, sizeof(struct cpu_info));
+
+ OFFSET(VCPU_arch_saved_context, struct vcpu, arch.saved_context);
}
+
/*
* Local variables:
* mode: C
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 0b55934..52a3128 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -14,7 +14,7 @@
#include "gic.h"
#include "vtimer.h"
-DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
+DEFINE_PER_CPU(struct pcpu_info, pcpu_info);
static void continue_idle_domain(struct vcpu *v)
{
@@ -44,7 +44,7 @@ void idle_loop(void)
static void ctxt_switch_from(struct vcpu *p)
{
-
+ context_saved(p);
}
static void ctxt_switch_to(struct vcpu *n)
@@ -52,52 +52,36 @@ static void ctxt_switch_to(struct vcpu *n)
p2m_load_VTTBR(n->domain);
}
-static void __context_switch(void)
+static void schedule_tail(struct vcpu *prev)
{
- struct cpu_user_regs *stack_regs = guest_cpu_user_regs();
- unsigned int cpu = smp_processor_id();
- struct vcpu *p = per_cpu(curr_vcpu, cpu);
- struct vcpu *n = current;
-
- ASSERT(p != n);
- ASSERT(cpumask_empty(n->vcpu_dirty_cpumask));
-
- if ( !is_idle_vcpu(p) )
- {
- memcpy(&p->arch.user_regs, stack_regs, CTXT_SWITCH_STACK_BYTES);
- ctxt_switch_from(p);
- }
+ /* Re-enable interrupts before restoring state which may fault. */
+ local_irq_enable();
- if ( !is_idle_vcpu(n) )
- {
- memcpy(stack_regs, &n->arch.user_regs, CTXT_SWITCH_STACK_BYTES);
- ctxt_switch_to(n);
- }
-
- per_cpu(curr_vcpu, cpu) = n;
+ ctxt_switch_from(prev);
+ /* TODO
+ update_runstate_area(current);
+ */
+ ctxt_switch_to(current);
}
-static void schedule_tail(struct vcpu *v)
+static void continue_new_vcpu(struct vcpu *prev)
{
- if ( is_idle_vcpu(v) )
- continue_idle_domain(v);
+ schedule_tail(prev);
+
+ if ( is_idle_vcpu(current) )
+ continue_idle_domain(current);
else
- continue_nonidle_domain(v);
+ continue_nonidle_domain(current);
}
void context_switch(struct vcpu *prev, struct vcpu *next)
{
- unsigned int cpu = smp_processor_id();
-
ASSERT(local_irq_is_enabled());
-
- printk("context switch %d:%d%s -> %d:%d%s\n",
- prev->domain->domain_id, prev->vcpu_id, is_idle_vcpu(prev)
? " (idle)" : "",
- next->domain->domain_id, next->vcpu_id, is_idle_vcpu(next)
? " (idle)" : "");
+ ASSERT(prev != next);
+ ASSERT(cpumask_empty(next->vcpu_dirty_cpumask));
/* TODO
- if (prev != next)
update_runstate_area(prev);
*/
@@ -105,60 +89,19 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
set_current(next);
- if ( (per_cpu(curr_vcpu, cpu) == next) ||
- (is_idle_vcpu(next) && cpu_online(cpu)) )
- {
- local_irq_enable();
- }
- else
- {
- __context_switch();
-
- /* Re-enable interrupts before restoring state which may fault. */
- local_irq_enable();
- }
-
- context_saved(prev);
-
- /* TODO
- if (prev != next)
- update_runstate_area(next);
- */
-
- schedule_tail(next);
- BUG();
+ prev = __context_switch(prev, next);
+ schedule_tail(prev);
}
void continue_running(struct vcpu *same)
{
- schedule_tail(same);
- BUG();
-}
-
-int __sync_local_execstate(void)
-{
- unsigned long flags;
- int switch_required;
-
- local_irq_save(flags);
-
- switch_required = (this_cpu(curr_vcpu) != current);
-
- if ( switch_required )
- {
- ASSERT(current == idle_vcpu[smp_processor_id()]);
- __context_switch();
- }
-
- local_irq_restore(flags);
-
- return switch_required;
+ /* Nothing to do */
}
void sync_local_execstate(void)
{
- (void)__sync_local_execstate();
+ /* Nothing to do -- no lazy switching */
}
void startup_cpu_idle_loop(void)
@@ -213,6 +156,18 @@ int vcpu_initialise(struct vcpu *v)
{
int rc = 0;
+ v->arch.stack = alloc_xenheap_pages(STACK_ORDER,
MEMF_node(vcpu_to_node(v)));
+ if ( v->arch.stack == NULL )
+ return -ENOMEM;
+
+ v->arch.cpu_info = (struct cpu_info *)(v->arch.stack
+ + STACK_SIZE
+ - sizeof(struct cpu_info));
+
+ memset(&v->arch.saved_context, 0, sizeof(v->arch.saved_context));
+ v->arch.saved_context.sp = (uint32_t)v->arch.cpu_info;
+ v->arch.saved_context.pc = (uint32_t)continue_new_vcpu;
+
if ( (rc = vcpu_vgic_init(v)) != 0 )
return rc;
@@ -224,7 +179,7 @@ int vcpu_initialise(struct vcpu *v)
void vcpu_destroy(struct vcpu *v)
{
-
+ free_xenheap_pages(v->arch.stack, STACK_ORDER);
}
int arch_domain_create(struct domain *d, unsigned int domcr_flags)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index cbbc0b9..9240209 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -5,6 +5,7 @@
#include <xen/domain_page.h>
#include <xen/sched.h>
#include <asm/irq.h>
+#include <asm/regs.h>
#include "gic.h"
#include "kernel.h"
@@ -71,7 +72,7 @@ int construct_dom0(struct domain *d)
int rc;
struct vcpu *v = d->vcpu[0];
- struct cpu_user_regs *regs = &v->arch.user_regs;
+ struct cpu_user_regs *regs =
&v->arch.cpu_info->guest_cpu_user_regs;
/* Sanity! */
BUG_ON(d->domain_id != 0);
diff --git a/xen/arch/arm/entry.S b/xen/arch/arm/entry.S
index 16a8f36..0b9cce5 100644
--- a/xen/arch/arm/entry.S
+++ b/xen/arch/arm/entry.S
@@ -105,3 +105,19 @@ ENTRY(return_to_hypervisor)
pop {r0-r12}
add sp, #(UREGS_R8_fiq - UREGS_sp); /* SP, LR, SPSR, PC */
eret
+
+/*
+ * struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next)
+ *
+ * r0 - prev
+ * r1 - next
+ *
+ * Returns prev in r0
+ */
+ENTRY(__context_switch)
+ add ip, r0, #VCPU_arch_saved_context
+ stmia ip!, {r4 - sl, fp, sp, lr} /* Save register state */
+
+ add r4, r1, #VCPU_arch_saved_context
+ ldmia r4, {r4 - sl, fp, sp, pc} /* Load registers and return */
+
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 4c1d89c..55d3df0 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -42,7 +42,7 @@
static unsigned int __initdata max_cpus = NR_CPUS;
/* Xen stack for bringing up the first CPU. */
-unsigned char init_stack[STACK_SIZE] __attribute__((__aligned__(STACK_SIZE)));
+unsigned char __initdata init_stack[STACK_SIZE]
__attribute__((__aligned__(STACK_SIZE)));
extern char __init_begin[], __init_end[], __bss_start[];
@@ -61,7 +61,6 @@ static void __init init_idle_domain(void)
{
scheduler_init();
set_current(idle_vcpu[0]);
- this_cpu(curr_vcpu) = current;
/* TODO: setup_idle_pagetable(); */
}
diff --git a/xen/include/asm-arm/current.h b/xen/include/asm-arm/current.h
index 826efa5..1753e8e 100644
--- a/xen/include/asm-arm/current.h
+++ b/xen/include/asm-arm/current.h
@@ -5,32 +5,44 @@
#include <xen/percpu.h>
#include <public/xen.h>
+#include <asm/percpu.h>
+
#ifndef __ASSEMBLY__
struct vcpu;
+struct pcpu_info {
+ unsigned int processor_id;
+ struct vcpu *current_vcpu;
+};
+
+DECLARE_PER_CPU(struct pcpu_info, pcpu_info);
+
+static inline struct pcpu_info *get_pcpu_info(void)
+{
+ return &this_cpu(pcpu_info);
+}
+
struct cpu_info {
struct cpu_user_regs guest_cpu_user_regs;
unsigned long elr;
- unsigned int processor_id;
- struct vcpu *current_vcpu;
- unsigned long per_cpu_offset;
+ unsigned long pad;
};
static inline struct cpu_info *get_cpu_info(void)
{
- register unsigned long sp asm ("sp");
- return (struct cpu_info *)((sp & ~(STACK_SIZE - 1)) + STACK_SIZE -
sizeof(struct cpu_info));
+ register unsigned long sp asm ("sp");
+ return (struct cpu_info *)((sp & ~(STACK_SIZE - 1)) + STACK_SIZE -
sizeof(struct cpu_info));
+ //return (struct cpu_info*)(get_pcpu_info()->current_vcpu->arch.stack
+ STACK_SIZE - sizeof(struct cpu_info));
}
-#define get_current() (get_cpu_info()->current_vcpu)
-#define set_current(vcpu) (get_cpu_info()->current_vcpu = (vcpu))
+#define get_current() (get_pcpu_info()->current_vcpu)
+#define set_current(vcpu) (get_pcpu_info()->current_vcpu = (vcpu))
#define current (get_current())
-#define get_processor_id() (get_cpu_info()->processor_id)
+#define get_processor_id() (get_pcpu_info()->processor_id)
#define set_processor_id(id) do { \
- struct cpu_info *ci__ = get_cpu_info(); \
- ci__->per_cpu_offset = __per_cpu_offset[ci__->processor_id = (id)]; \
+ get_pcpu_info()->processor_id = (id); \
} while (0)
#define guest_cpu_user_regs() (&get_cpu_info()->guest_cpu_user_regs)
@@ -39,15 +51,8 @@ static inline struct cpu_info *get_cpu_info(void)
__asm__ __volatile__ ( \
"mov sp,%0; b "STR(__fn) \
: : "r" (guest_cpu_user_regs()) : "memory" )
-#endif
-
-/*
- * Which VCPU''s state is currently running on each CPU?
- * This is not necesasrily the same as ''current'' as a CPU may
be
- * executing a lazy state switch.
- */
-DECLARE_PER_CPU(struct vcpu *, curr_vcpu);
+#endif
#endif /* __ARM_CURRENT_H__ */
/*
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 3372d14..c1afd19 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -47,7 +47,26 @@ struct arch_domain
struct arch_vcpu
{
- struct cpu_user_regs user_regs;
+ struct {
+ uint32_t r4;
+ uint32_t r5;
+ uint32_t r6;
+ uint32_t r7;
+ uint32_t r8;
+ uint32_t r9;
+ uint32_t sl;
+ uint32_t fp;
+ uint32_t sp;
+ uint32_t pc;
+ } saved_context;
+
+ void *stack;
+
+ /*
+ * Points into ->stack, more convenient than doing pointer arith
+ * all the time.
+ */
+ struct cpu_info *cpu_info;
uint32_t sctlr;
uint32_t ttbr0, ttbr1, ttbcr;
diff --git a/xen/include/asm-arm/regs.h b/xen/include/asm-arm/regs.h
index ee095bf..54f6ed8 100644
--- a/xen/include/asm-arm/regs.h
+++ b/xen/include/asm-arm/regs.h
@@ -28,9 +28,7 @@
(diff == 0); \
})
-#define return_reg(v) ((v)->arch.user_regs.r0)
-
-#define CTXT_SWITCH_STACK_BYTES (sizeof(struct cpu_user_regs))
+#define return_reg(v) ((v)->arch.cpu_info->guest_cpu_user_regs.r0)
#endif /* __ARM_REGS_H__ */
/*
diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index 731d89f..7963ea5 100644
--- a/xen/include/asm-arm/system.h
+++ b/xen/include/asm-arm/system.h
@@ -191,6 +191,8 @@ static inline int local_fiq_is_enabled(void)
return !!(flags & PSR_FIQ_MASK);
}
+extern struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next);
+
#endif
/*
* Local variables:
--
1.7.2.5
At 16:49 +0000 on 15 Feb (1329324592), Ian Campbell wrote:> +struct pcpu_info { > + unsigned int processor_id; > + struct vcpu *current_vcpu; > +}; > + > +DECLARE_PER_CPU(struct pcpu_info, pcpu_info);> +static inline struct pcpu_info *get_pcpu_info(void) > +{ > + return &this_cpu(pcpu_info); > +} > +I don''t think it''s worth declaring a struct and accessors for this; we should just have current_vcpu as an ordinary per-cpu variable. Storing the CPU ID in the per-pcpu area only happens to work because per-cpu areas are a noop right now. I have a patch that re-enables them properly but for that we''ll need a proper way of getting the CPU id. In the meantime I think it would be less confusing just to hard-code it as zero than to do this. :) We could use the physical CPU ID register; I don''t know whether it would be faster to stash the ID on the (per-vcpu) stack and update it during context switch. Aside from that, this patch looks OK to me. Cheers, Tim.
On Sat, 2012-02-18 at 13:52 +0000, Tim Deegan wrote:> At 16:49 +0000 on 15 Feb (1329324592), Ian Campbell wrote: > > +struct pcpu_info { > > + unsigned int processor_id; > > + struct vcpu *current_vcpu; > > +}; > > + > > +DECLARE_PER_CPU(struct pcpu_info, pcpu_info); > > > +static inline struct pcpu_info *get_pcpu_info(void) > > +{ > > + return &this_cpu(pcpu_info); > > +} > > + > > I don''t think it''s worth declaring a struct and accessors for this; we > should just have current_vcpu as an ordinary per-cpu variable.That makes sense.> Storing the CPU ID in the per-pcpu area only happens to work because > per-cpu areas are a noop right now. I have a patch that re-enables them > properly but for that we''ll need a proper way of getting the CPU id.I had imagined that we would have per pVCPU page tables so the current CPU''s per-pcpu area would always be at the same location. If that is not (going to be) the case then I''ll stash it on the VCPU stack instead. Thinking about it now playing tricks with the PTs does make it tricky on the rare occasions when you want to access another pCPUs per area. Speaking of per-cpu areas -- I did notice a strange behaviour while debugging this. It seemed that a barrier() was not sufficient to keep the processor from caching the value of "current" in a register (i.e it would load into r6 before the barrier and use r6 after). I figured this was probably an unfortunate side effect of the current nobbled per-pcpu areas and would be fixed as part of your SMP bringup stuff.> We could use the physical CPU ID register; I don''t know whether it > would be faster to stash the ID on the (per-vcpu) stack and update it > during context switch.Does h/w CPU ID correspond to the s/w one in our circumstances? Might they be very sparse or something inconvenient like that? I''d expect pulling things from registers to be faster in the normal case but in this specific scenario I''d imagine the base of the stack will be pretty cache hot since it has all the guest state in it etc which we''ve probably fairly recently pushed to or are about to pop from. [...]> Aside from that, this patch looks OK to me.Thanks I''ll repost next week with the fixes you suggest. Ian.
At 08:44 +0000 on 19 Feb (1329641061), Ian Campbell wrote:> > Storing the CPU ID in the per-pcpu area only happens to work because > > per-cpu areas are a noop right now. I have a patch that re-enables them > > properly but for that we''ll need a proper way of getting the CPU id. > > I had imagined that we would have per pVCPU page tables so the current > CPU''s per-pcpu area would always be at the same location. If that is not > (going to be) the case then I''ll stash it on the VCPU stack instead.Yes I''d thought that too but then when I came to implement it up...> Thinking about it now playing tricks with the PTs does make it tricky on > the rare occasions when you want to access another pCPUs per area.... I saw that and since I then had to use the normal relocation tricks I didn''t bother with the local-var special case. Could still do it if it turns out to be a perf win (but w/out hardware to measure, I think I''ll leave the optimizations alone for now).> Speaking of per-cpu areas -- I did notice a strange behaviour while > debugging this. It seemed that a barrier() was not sufficient to keep > the processor from caching the value of "current" in a register (i.e it > would load into r6 before the barrier and use r6 after). I figured this > was probably an unfortunate side effect of the current nobbled per-pcpu > areas and would be fixed as part of your SMP bringup stuff.Wierd. Must check that when I rebase the SMP patches.> > We could use the physical CPU ID register; I don''t know whether it > > would be faster to stash the ID on the (per-vcpu) stack and update it > > during context switch. > > Does h/w CPU ID correspond to the s/w one in our circumstances? Might > they be very sparse or something inconvenient like that?It does on all the h/w we support :) but yes it could be sparse, encoding NUMA topology.> I''d expect pulling things from registers to be faster in the normal case > but in this specific scenario I''d imagine the base of the stack will be > pretty cache hot since it has all the guest state in it etc which we''ve > probably fairly recently pushed to or are about to pop from.Agreed. Tim.
We do not do any lazy state switching. Outside of context_switch() the current
stack is always that of the VCPU which current returns.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Tim Deegan <tim@xen.org>
---
xen/arch/arm/asm-offsets.c | 4 ++
xen/arch/arm/domain.c | 113 ++++++++++++----------------------------
xen/arch/arm/domain_build.c | 3 +-
xen/arch/arm/entry.S | 16 ++++++
xen/arch/arm/setup.c | 5 +-
xen/include/asm-arm/current.h | 35 +++++++------
xen/include/asm-arm/domain.h | 21 +++++++-
xen/include/asm-arm/regs.h | 4 +-
xen/include/asm-arm/system.h | 2 +
9 files changed, 101 insertions(+), 102 deletions(-)
diff --git a/xen/arch/arm/asm-offsets.c b/xen/arch/arm/asm-offsets.c
index ee5d5d4..cc1a72a 100644
--- a/xen/arch/arm/asm-offsets.c
+++ b/xen/arch/arm/asm-offsets.c
@@ -7,6 +7,7 @@
#include <xen/config.h>
#include <xen/types.h>
+#include <xen/sched.h>
#include <public/xen.h>
#include <asm/current.h>
@@ -65,7 +66,10 @@ void __dummy__(void)
BLANK();
DEFINE(CPUINFO_sizeof, sizeof(struct cpu_info));
+
+ OFFSET(VCPU_arch_saved_context, struct vcpu, arch.saved_context);
}
+
/*
* Local variables:
* mode: C
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 0b55934..a0b9d38 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -44,7 +44,7 @@ void idle_loop(void)
static void ctxt_switch_from(struct vcpu *p)
{
-
+ context_saved(p);
}
static void ctxt_switch_to(struct vcpu *n)
@@ -52,52 +52,36 @@ static void ctxt_switch_to(struct vcpu *n)
p2m_load_VTTBR(n->domain);
}
-static void __context_switch(void)
+static void schedule_tail(struct vcpu *prev)
{
- struct cpu_user_regs *stack_regs = guest_cpu_user_regs();
- unsigned int cpu = smp_processor_id();
- struct vcpu *p = per_cpu(curr_vcpu, cpu);
- struct vcpu *n = current;
-
- ASSERT(p != n);
- ASSERT(cpumask_empty(n->vcpu_dirty_cpumask));
-
- if ( !is_idle_vcpu(p) )
- {
- memcpy(&p->arch.user_regs, stack_regs, CTXT_SWITCH_STACK_BYTES);
- ctxt_switch_from(p);
- }
+ /* Re-enable interrupts before restoring state which may fault. */
+ local_irq_enable();
- if ( !is_idle_vcpu(n) )
- {
- memcpy(stack_regs, &n->arch.user_regs, CTXT_SWITCH_STACK_BYTES);
- ctxt_switch_to(n);
- }
-
- per_cpu(curr_vcpu, cpu) = n;
+ ctxt_switch_from(prev);
+ /* TODO
+ update_runstate_area(current);
+ */
+ ctxt_switch_to(current);
}
-static void schedule_tail(struct vcpu *v)
+static void continue_new_vcpu(struct vcpu *prev)
{
- if ( is_idle_vcpu(v) )
- continue_idle_domain(v);
+ schedule_tail(prev);
+
+ if ( is_idle_vcpu(current) )
+ continue_idle_domain(current);
else
- continue_nonidle_domain(v);
+ continue_nonidle_domain(current);
}
void context_switch(struct vcpu *prev, struct vcpu *next)
{
- unsigned int cpu = smp_processor_id();
-
ASSERT(local_irq_is_enabled());
-
- printk("context switch %d:%d%s -> %d:%d%s\n",
- prev->domain->domain_id, prev->vcpu_id, is_idle_vcpu(prev)
? " (idle)" : "",
- next->domain->domain_id, next->vcpu_id, is_idle_vcpu(next)
? " (idle)" : "");
+ ASSERT(prev != next);
+ ASSERT(cpumask_empty(next->vcpu_dirty_cpumask));
/* TODO
- if (prev != next)
update_runstate_area(prev);
*/
@@ -105,60 +89,19 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
set_current(next);
- if ( (per_cpu(curr_vcpu, cpu) == next) ||
- (is_idle_vcpu(next) && cpu_online(cpu)) )
- {
- local_irq_enable();
- }
- else
- {
- __context_switch();
-
- /* Re-enable interrupts before restoring state which may fault. */
- local_irq_enable();
- }
-
- context_saved(prev);
-
- /* TODO
- if (prev != next)
- update_runstate_area(next);
- */
-
- schedule_tail(next);
- BUG();
+ prev = __context_switch(prev, next);
+ schedule_tail(prev);
}
void continue_running(struct vcpu *same)
{
- schedule_tail(same);
- BUG();
-}
-
-int __sync_local_execstate(void)
-{
- unsigned long flags;
- int switch_required;
-
- local_irq_save(flags);
-
- switch_required = (this_cpu(curr_vcpu) != current);
-
- if ( switch_required )
- {
- ASSERT(current == idle_vcpu[smp_processor_id()]);
- __context_switch();
- }
-
- local_irq_restore(flags);
-
- return switch_required;
+ /* Nothing to do */
}
void sync_local_execstate(void)
{
- (void)__sync_local_execstate();
+ /* Nothing to do -- no lazy switching */
}
void startup_cpu_idle_loop(void)
@@ -213,6 +156,18 @@ int vcpu_initialise(struct vcpu *v)
{
int rc = 0;
+ v->arch.stack = alloc_xenheap_pages(STACK_ORDER,
MEMF_node(vcpu_to_node(v)));
+ if ( v->arch.stack == NULL )
+ return -ENOMEM;
+
+ v->arch.cpu_info = (struct cpu_info *)(v->arch.stack
+ + STACK_SIZE
+ - sizeof(struct cpu_info));
+
+ memset(&v->arch.saved_context, 0, sizeof(v->arch.saved_context));
+ v->arch.saved_context.sp = (uint32_t)v->arch.cpu_info;
+ v->arch.saved_context.pc = (uint32_t)continue_new_vcpu;
+
if ( (rc = vcpu_vgic_init(v)) != 0 )
return rc;
@@ -224,7 +179,7 @@ int vcpu_initialise(struct vcpu *v)
void vcpu_destroy(struct vcpu *v)
{
-
+ free_xenheap_pages(v->arch.stack, STACK_ORDER);
}
int arch_domain_create(struct domain *d, unsigned int domcr_flags)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index cbbc0b9..9240209 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -5,6 +5,7 @@
#include <xen/domain_page.h>
#include <xen/sched.h>
#include <asm/irq.h>
+#include <asm/regs.h>
#include "gic.h"
#include "kernel.h"
@@ -71,7 +72,7 @@ int construct_dom0(struct domain *d)
int rc;
struct vcpu *v = d->vcpu[0];
- struct cpu_user_regs *regs = &v->arch.user_regs;
+ struct cpu_user_regs *regs =
&v->arch.cpu_info->guest_cpu_user_regs;
/* Sanity! */
BUG_ON(d->domain_id != 0);
diff --git a/xen/arch/arm/entry.S b/xen/arch/arm/entry.S
index 16a8f36..0b9cce5 100644
--- a/xen/arch/arm/entry.S
+++ b/xen/arch/arm/entry.S
@@ -105,3 +105,19 @@ ENTRY(return_to_hypervisor)
pop {r0-r12}
add sp, #(UREGS_R8_fiq - UREGS_sp); /* SP, LR, SPSR, PC */
eret
+
+/*
+ * struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next)
+ *
+ * r0 - prev
+ * r1 - next
+ *
+ * Returns prev in r0
+ */
+ENTRY(__context_switch)
+ add ip, r0, #VCPU_arch_saved_context
+ stmia ip!, {r4 - sl, fp, sp, lr} /* Save register state */
+
+ add r4, r1, #VCPU_arch_saved_context
+ ldmia r4, {r4 - sl, fp, sp, pc} /* Load registers and return */
+
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 4c1d89ce..4c0244c 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -42,7 +42,7 @@
static unsigned int __initdata max_cpus = NR_CPUS;
/* Xen stack for bringing up the first CPU. */
-unsigned char init_stack[STACK_SIZE] __attribute__((__aligned__(STACK_SIZE)));
+unsigned char __initdata init_stack[STACK_SIZE]
__attribute__((__aligned__(STACK_SIZE)));
extern char __init_begin[], __init_end[], __bss_start[];
@@ -61,7 +61,6 @@ static void __init init_idle_domain(void)
{
scheduler_init();
set_current(idle_vcpu[0]);
- this_cpu(curr_vcpu) = current;
/* TODO: setup_idle_pagetable(); */
}
@@ -175,7 +174,7 @@ void __init start_xen(unsigned long boot_phys_offset,
console_init_preirq();
#endif
- set_current((struct vcpu *)0xfffff000); /* debug sanity */
+ __set_current((struct vcpu *)0xfffff000); /* debug sanity */
idle_vcpu[0] = current;
set_processor_id(0); /* needed early, for smp_processor_id() */
diff --git a/xen/include/asm-arm/current.h b/xen/include/asm-arm/current.h
index 826efa5..72d4945 100644
--- a/xen/include/asm-arm/current.h
+++ b/xen/include/asm-arm/current.h
@@ -5,49 +5,54 @@
#include <xen/percpu.h>
#include <public/xen.h>
+#include <asm/percpu.h>
+
#ifndef __ASSEMBLY__
struct vcpu;
+/*
+ * Which VCPU is "current" on this PCPU.
+ */
+DECLARE_PER_CPU(struct vcpu *, curr_vcpu);
+
struct cpu_info {
struct cpu_user_regs guest_cpu_user_regs;
unsigned long elr;
+ /* The following are valid iff this VCPU is current */
unsigned int processor_id;
- struct vcpu *current_vcpu;
unsigned long per_cpu_offset;
+ unsigned int pad;
};
static inline struct cpu_info *get_cpu_info(void)
{
- register unsigned long sp asm ("sp");
- return (struct cpu_info *)((sp & ~(STACK_SIZE - 1)) + STACK_SIZE -
sizeof(struct cpu_info));
+ register unsigned long sp asm ("sp");
+ return (struct cpu_info *)((sp & ~(STACK_SIZE - 1)) + STACK_SIZE -
sizeof(struct cpu_info));
}
-#define get_current() (get_cpu_info()->current_vcpu)
-#define set_current(vcpu) (get_cpu_info()->current_vcpu = (vcpu))
-#define current (get_current())
-
#define get_processor_id() (get_cpu_info()->processor_id)
#define set_processor_id(id) do { \
struct cpu_info *ci__ = get_cpu_info(); \
ci__->per_cpu_offset = __per_cpu_offset[ci__->processor_id = (id)]; \
} while (0)
+#define get_current() (this_cpu(curr_vcpu))
+#define __set_current(vcpu) (this_cpu(curr_vcpu) = (vcpu))
+#define set_current(vcpu) do { \
+ vcpu->arch.cpu_info->processor_id = get_processor_id(); \
+ __set_current(vcpu); \
+} while (0)
+#define current (get_current())
+
#define guest_cpu_user_regs() (&get_cpu_info()->guest_cpu_user_regs)
#define reset_stack_and_jump(__fn) \
__asm__ __volatile__ ( \
"mov sp,%0; b "STR(__fn) \
: : "r" (guest_cpu_user_regs()) : "memory" )
-#endif
-
-/*
- * Which VCPU''s state is currently running on each CPU?
- * This is not necesasrily the same as ''current'' as a CPU may
be
- * executing a lazy state switch.
- */
-DECLARE_PER_CPU(struct vcpu *, curr_vcpu);
+#endif
#endif /* __ARM_CURRENT_H__ */
/*
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 3372d14..c1afd19 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -47,7 +47,26 @@ struct arch_domain
struct arch_vcpu
{
- struct cpu_user_regs user_regs;
+ struct {
+ uint32_t r4;
+ uint32_t r5;
+ uint32_t r6;
+ uint32_t r7;
+ uint32_t r8;
+ uint32_t r9;
+ uint32_t sl;
+ uint32_t fp;
+ uint32_t sp;
+ uint32_t pc;
+ } saved_context;
+
+ void *stack;
+
+ /*
+ * Points into ->stack, more convenient than doing pointer arith
+ * all the time.
+ */
+ struct cpu_info *cpu_info;
uint32_t sctlr;
uint32_t ttbr0, ttbr1, ttbcr;
diff --git a/xen/include/asm-arm/regs.h b/xen/include/asm-arm/regs.h
index ee095bf..54f6ed8 100644
--- a/xen/include/asm-arm/regs.h
+++ b/xen/include/asm-arm/regs.h
@@ -28,9 +28,7 @@
(diff == 0); \
})
-#define return_reg(v) ((v)->arch.user_regs.r0)
-
-#define CTXT_SWITCH_STACK_BYTES (sizeof(struct cpu_user_regs))
+#define return_reg(v) ((v)->arch.cpu_info->guest_cpu_user_regs.r0)
#endif /* __ARM_REGS_H__ */
/*
diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index 731d89f..7963ea5 100644
--- a/xen/include/asm-arm/system.h
+++ b/xen/include/asm-arm/system.h
@@ -191,6 +191,8 @@ static inline int local_fiq_is_enabled(void)
return !!(flags & PSR_FIQ_MASK);
}
+extern struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next);
+
#endif
/*
* Local variables:
--
1.7.2.5
At 14:43 +0000 on 20 Feb (1329749035), Ian Campbell wrote:> We do not do any lazy state switching. Outside of context_switch() the current > stack is always that of the VCPU which current returns. > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > Cc: Tim Deegan <tim@xen.org>Acked-by: Tim Deegan <tim@xen.org>
On Mon, 2012-02-20 at 14:58 +0000, Tim Deegan wrote:> At 14:43 +0000 on 20 Feb (1329749035), Ian Campbell wrote: > > We do not do any lazy state switching. Outside of context_switch() the current > > stack is always that of the VCPU which current returns. > > > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > > Cc: Tim Deegan <tim@xen.org> > > Acked-by: Tim Deegan <tim@xen.org>Thanks, committed.