Hi Dario,
On 4/20/19 4:24 PM, Dario Faggioli wrote:
In schedule(), if we pick, as the next vcpu to run (next) the same one
that is running already (prev), we never get to call context_switch().
We can, therefore, get rid of all the `if`-s testing prev and next being
different, trading them with an ASSERT() (on ARM, the ASSERT() was even
already there!)
Signed-off-by: Dario Faggioli <dfaggi...@suse.com>
Suggested-by: Juergen Gross <jgr...@suse.com>
For Arm:
Acked-by: Julien Grall <julien.gr...@arm.com>
Cheers,
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Julien Grall <julien.gr...@arm.com>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Andrew Cooper <andrew.coop...@citrix.com>
Cc: Wei Liu <wei.l...@citrix.com>
Cc: "Roger Pau Monné" <roger....@citrix.com>
Cc: George Dunlap <george.dun...@citrix.com>
Cc: Juergen Gross <jgr...@suse.com>
---
xen/arch/arm/domain.c | 3 +--
xen/arch/x86/domain.c | 22 ++++++++--------------
2 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 6dc633ed50..915ae0b4c6 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -343,8 +343,7 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
ASSERT(prev != next);
ASSERT(!vcpu_cpu_dirty(next));
- if ( prev != next )
- update_runstate_area(prev);
+ update_runstate_area(prev);
local_irq_disable();
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 9eaa978ce5..d2d9f2fc3c 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1721,6 +1721,7 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
const struct domain *prevd = prev->domain, *nextd = next->domain;
unsigned int dirty_cpu = next->dirty_cpu;
+ ASSERT(prev != next);
ASSERT(local_irq_is_enabled());
get_cpu_info()->use_pv_cr3 = false;
@@ -1732,12 +1733,9 @@ void context_switch(struct vcpu *prev, struct vcpu *next)
flush_mask(cpumask_of(dirty_cpu), FLUSH_VCPU_STATE);
}
- if ( prev != next )
- {
- _update_runstate_area(prev);
- vpmu_switch_from(prev);
- np2m_schedule(NP2M_SCHEDLE_OUT);
- }
+ _update_runstate_area(prev);
+ vpmu_switch_from(prev);
+ np2m_schedule(NP2M_SCHEDLE_OUT);
if ( is_hvm_domain(prevd) && !list_empty(&prev->arch.hvm.tm_list) )
pt_save_timer(prev);
@@ -1794,14 +1792,10 @@ void context_switch(struct vcpu *prev, struct vcpu
*next)
context_saved(prev);
- if ( prev != next )
- {
- _update_runstate_area(next);
-
- /* Must be done with interrupts enabled */
- vpmu_switch_to(next);
- np2m_schedule(NP2M_SCHEDLE_IN);
- }
+ _update_runstate_area(next);
+ /* Must be done with interrupts enabled */
+ vpmu_switch_to(next);
+ np2m_schedule(NP2M_SCHEDLE_IN);
/* Ensure that the vcpu has an up-to-date time base. */
update_vcpu_system_time(next);
--
Julien Grall
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