| Message ID | 1413487800-7162-9-git-send-email-kernelfans@gmail.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
On 10/17/2014 12:59 AM, kernelfans@gmail.com wrote: > The secondary thread can only jump back to host until primary has set > up the env. Add host_ready field in kvm_vcore to sync this action. Do we need to do this? We already synchronize among the sibling threads when there is a need to enter the host. Today too, the secondaries may require host kernel's intervention and there is already code in which under such circumstances, the secondaries set the HDEC of the sibling threads and wait for the primary to switch context. I see the code under secondary_too_late. Besides this, do we need anything additional to synchronize the exit to host path? IIUC, we will need synchronization only in the entry to guest path. And of course there will be more guest exits now since the secondaries are as alive in the host as the primary and will have scheduling interrupts atleast, forcing them to exit to host. This cannot be trivially solved unless we can isolate these threads in some way. Regards Preeti U Murthy > > Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/kvm_host.h | 3 +++ > arch/powerpc/kernel/asm-offsets.c | 3 +++ > arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 ++++++++++- > 3 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index 9a3355e..1310e03 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -305,6 +305,9 @@ struct kvmppc_vcore { > u32 arch_compat; > ulong pcr; > ulong dpdes; /* doorbell state (POWER8) */ > +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY > + u8 host_ready; > +#endif > void *mpp_buffer; /* Micro Partition Prefetch buffer */ > bool mpp_buffer_is_valid; > }; > diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c > index 0faa8fe..9c04ac2 100644 > --- a/arch/powerpc/kernel/asm-offsets.c > +++ b/arch/powerpc/kernel/asm-offsets.c > @@ -562,6 +562,9 @@ int main(void) > DEFINE(VCORE_LPCR, offsetof(struct kvmppc_vcore, lpcr)); > DEFINE(VCORE_PCR, offsetof(struct kvmppc_vcore, pcr)); > DEFINE(VCORE_DPDES, offsetof(struct kvmppc_vcore, dpdes)); > +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY > + DEFINE(VCORE_HOST_READY, offsetof(struct kvmppc_vcore, host_ready)); > +#endif > DEFINE(VCPU_SLB_E, offsetof(struct kvmppc_slb, orige)); > DEFINE(VCPU_SLB_V, offsetof(struct kvmppc_slb, origv)); > DEFINE(VCPU_SLB_SIZE, sizeof(struct kvmppc_slb)); > diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > index 254038b..89ea16c 100644 > --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S > +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > @@ -351,7 +351,11 @@ kvm_do_nap: > kvm_secondary_exit_trampoline: > > /* all register is free to use, later kvmppc_secondary_stopper_exit set up them*/ > - //loop-wait for the primary to signal that host env is ready > + /* wait until the primary to set up host env */ > + ld r5, HSTATE_KVM_VCORE(r13) > + ld r0, VCORE_HOST_READY(r5) > + cmp r0, //primary is ready? > + bne kvm_secondary_exit_trampoline > > LOAD_REG_ADDR(r5, kvmppc_secondary_stopper_exit) > /* fixme, load msr from lpaca stack */ > @@ -1821,6 +1825,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) > li r0, KVM_GUEST_MODE_NONE > stb r0, HSTATE_IN_GUEST(r13) > > +#ifdef PPCKVM_ENABLE_SECONDARY > + /* signal the secondary that host env is ready */ > + li r0, 1 > + stb r0, VCORE_HOST_READY(r5) > +#endif > ld r0, 112+PPC_LR_STKOFF(r1) > addi r1, r1, 112 > mtlr r0 >
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 9a3355e..1310e03 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -305,6 +305,9 @@ struct kvmppc_vcore { u32 arch_compat; ulong pcr; ulong dpdes; /* doorbell state (POWER8) */ +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY + u8 host_ready; +#endif void *mpp_buffer; /* Micro Partition Prefetch buffer */ bool mpp_buffer_is_valid; }; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 0faa8fe..9c04ac2 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -562,6 +562,9 @@ int main(void) DEFINE(VCORE_LPCR, offsetof(struct kvmppc_vcore, lpcr)); DEFINE(VCORE_PCR, offsetof(struct kvmppc_vcore, pcr)); DEFINE(VCORE_DPDES, offsetof(struct kvmppc_vcore, dpdes)); +#ifdef CONFIG_KVMPPC_ENABLE_SECONDARY + DEFINE(VCORE_HOST_READY, offsetof(struct kvmppc_vcore, host_ready)); +#endif DEFINE(VCPU_SLB_E, offsetof(struct kvmppc_slb, orige)); DEFINE(VCPU_SLB_V, offsetof(struct kvmppc_slb, origv)); DEFINE(VCPU_SLB_SIZE, sizeof(struct kvmppc_slb)); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 254038b..89ea16c 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -351,7 +351,11 @@ kvm_do_nap: kvm_secondary_exit_trampoline: /* all register is free to use, later kvmppc_secondary_stopper_exit set up them*/ - //loop-wait for the primary to signal that host env is ready + /* wait until the primary to set up host env */ + ld r5, HSTATE_KVM_VCORE(r13) + ld r0, VCORE_HOST_READY(r5) + cmp r0, //primary is ready? + bne kvm_secondary_exit_trampoline LOAD_REG_ADDR(r5, kvmppc_secondary_stopper_exit) /* fixme, load msr from lpaca stack */ @@ -1821,6 +1825,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) li r0, KVM_GUEST_MODE_NONE stb r0, HSTATE_IN_GUEST(r13) +#ifdef PPCKVM_ENABLE_SECONDARY + /* signal the secondary that host env is ready */ + li r0, 1 + stb r0, VCORE_HOST_READY(r5) +#endif ld r0, 112+PPC_LR_STKOFF(r1) addi r1, r1, 112 mtlr r0
The secondary thread can only jump back to host until primary has set up the env. Add host_ready field in kvm_vcore to sync this action. Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> --- arch/powerpc/include/asm/kvm_host.h | 3 +++ arch/powerpc/kernel/asm-offsets.c | 3 +++ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 ++++++++++- 3 files changed, 16 insertions(+), 1 deletion(-)