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| author | Paul Mackerras | 2015-03-28 04:21:09 +0100 |
|---|---|---|
| committer | Alexander Graf | 2015-04-21 15:21:33 +0200 |
| commit | 7d6c40da198ac18bd5dd2cd18628d5b4c615d842 (patch) | |
| tree | 2c2e25ea051d2a569ae8332742fb27f59dff5eb3 /arch/powerpc/include | |
| parent | KVM: PPC: Book3S HV: Use decrementer to wake napping threads (diff) | |
| download | kernel-qcow2-linux-7d6c40da198ac18bd5dd2cd18628d5b4c615d842.tar.gz kernel-qcow2-linux-7d6c40da198ac18bd5dd2cd18628d5b4c615d842.tar.xz kernel-qcow2-linux-7d6c40da198ac18bd5dd2cd18628d5b4c615d842.zip | |
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count
Currently, the entry_exit_count field in the kvmppc_vcore struct
contains two 8-bit counts, one of the threads that have started entering
the guest, and one of the threads that have started exiting the guest.
This changes it to an entry_exit_map field which contains two bitmaps
of 8 bits each. The advantage of doing this is that it gives us a
bitmap of which threads need to be signalled when exiting the guest.
That means that we no longer need to use the trick of setting the
HDEC to 0 to pull the other threads out of the guest, which led in
some cases to a spurious HDEC interrupt on the next guest entry.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 1517faac9b98..d67a83830bd1 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -263,15 +263,15 @@ struct kvm_arch { /* * Struct for a virtual core. - * Note: entry_exit_count combines an entry count in the bottom 8 bits - * and an exit count in the next 8 bits. This is so that we can - * atomically increment the entry count iff the exit count is 0 - * without taking the lock. + * Note: entry_exit_map combines a bitmap of threads that have entered + * in the bottom 8 bits and a bitmap of threads that have exited in the + * next 8 bits. This is so that we can atomically set the entry bit + * iff the exit map is 0 without taking a lock. */ struct kvmppc_vcore { int n_runnable; int num_threads; - int entry_exit_count; + int entry_exit_map; int napping_threads; int first_vcpuid; u16 pcpu; @@ -296,8 +296,9 @@ struct kvmppc_vcore { ulong conferring_threads; }; -#define VCORE_ENTRY_COUNT(vc) ((vc)->entry_exit_count & 0xff) -#define VCORE_EXIT_COUNT(vc) ((vc)->entry_exit_count >> 8) +#define VCORE_ENTRY_MAP(vc) ((vc)->entry_exit_map & 0xff) +#define VCORE_EXIT_MAP(vc) ((vc)->entry_exit_map >> 8) +#define VCORE_IS_EXITING(vc) (VCORE_EXIT_MAP(vc) != 0) /* Values for vcore_state */ #define VCORE_INACTIVE 0 |