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authorPaul Mackerras <paulus@samba.org>2015-06-24 21:18:03 +1000
committerAlexander Graf <agraf@suse.de>2015-08-22 11:16:17 +0200
commitec257165082616841a354dd915801ed43e3553be (patch)
tree9d88c91517f5cf7879f7fb1121b88c4e797a390c /arch/powerpc/kernel/asm-offsets.c
parent845ac985cf8e3d52939dbe2446d91e47e91a07b6 (diff)
downloadblackbird-op-linux-ec257165082616841a354dd915801ed43e3553be.tar.gz
blackbird-op-linux-ec257165082616841a354dd915801ed43e3553be.zip
KVM: PPC: Book3S HV: Make use of unused threads when running guests
When running a virtual core of a guest that is configured with fewer threads per core than the physical cores have, the extra physical threads are currently unused. This makes it possible to use them to run one or more other virtual cores from the same guest when certain conditions are met. This applies on POWER7, and on POWER8 to guests with one thread per virtual core. (It doesn't apply to POWER8 guests with multiple threads per vcore because they require a 1-1 virtual to physical thread mapping in order to be able to use msgsndp and the TIR.) The idea is that we maintain a list of preempted vcores for each physical cpu (i.e. each core, since the host runs single-threaded). Then, when a vcore is about to run, it checks to see if there are any vcores on the list for its physical cpu that could be piggybacked onto this vcore's execution. If so, those additional vcores are put into state VCORE_PIGGYBACK and their runnable VCPU threads are started as well as the original vcore, which is called the master vcore. After the vcores have exited the guest, the extra ones are put back onto the preempted list if any of their VCPUs are still runnable and not idle. This means that vcpu->arch.ptid is no longer necessarily the same as the physical thread that the vcpu runs on. In order to make it easier for code that wants to send an IPI to know which CPU to target, we now store that in a new field in struct vcpu_arch, called thread_cpu. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Tested-by: Laurent Vivier <lvivier@redhat.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/powerpc/kernel/asm-offsets.c')
-rw-r--r--arch/powerpc/kernel/asm-offsets.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 98230579d99c..a78cdbf9b622 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -512,6 +512,8 @@ int main(void)
DEFINE(VCPU_VPA, offsetof(struct kvm_vcpu, arch.vpa.pinned_addr));
DEFINE(VCPU_VPA_DIRTY, offsetof(struct kvm_vcpu, arch.vpa.dirty));
DEFINE(VCPU_HEIR, offsetof(struct kvm_vcpu, arch.emul_inst));
+ DEFINE(VCPU_CPU, offsetof(struct kvm_vcpu, cpu));
+ DEFINE(VCPU_THREAD_CPU, offsetof(struct kvm_vcpu, arch.thread_cpu));
#endif
#ifdef CONFIG_PPC_BOOK3S
DEFINE(VCPU_VCPUID, offsetof(struct kvm_vcpu, vcpu_id));
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