It would be tempting to turn the 'pause' state into a flag.
However, this cannot easily be done as it is updated out of context,
while all the flags expect to only be updated from the vcpu thread.
Turning it into a flag would require to make all flag updates
atomic, which isn't necessary desireable.
Document this, and take this opportunity to move the field next
to the flag sets, filling a hole in the vcpu structure.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 83f3dae4333a..8c47b7f8ef92 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -344,6 +344,15 @@ struct kvm_vcpu_arch {
/* State flags, unused by the hypervisor code */
u8 sflags;
+ /*
+ * Don't run the guest (internal implementation need).
+ *
+ * Contrary to the flags above, this is set/cleared outside of
+ * a vcpu context, and thus cannot be mixed with the flags
+ * themselves (or the flag accesses need to be made atomic).
+ */
+ bool pause;
+
/*
* We maintain more than a single set of debug registers to support
* debugging the guest from the host and to maintain separate host and
@@ -397,9 +406,6 @@ struct kvm_vcpu_arch {
/* vcpu power state */
struct kvm_mp_state mp_state;
- /* Don't run the guest (internal implementation need) */
- bool pause;
-
/* Cache some mmu pages needed inside spinlock regions */
struct kvm_mmu_memory_cache mmu_page_cache;
--
2.34.1
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