KVM: PPC: Book3S HV P9: implement kvmppc_xive_pull_vcpu in C

This is more symmetric with kvmppc_xive_push_vcpu, and has the advantage
that it runs with the MMU on.

The extra test added to the asm will go away with a future change.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-9-npiggin@gmail.com

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 5bf8ae9bb2cc144ccbe85cfa26a0b7a4c6c28657..8c10c342716667add84849f1b0528fb64cabb23f 100644 (file)
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -671,6 +671,7 @@ extern int kvmppc_xive_set_icp(struct kvm_vcpu *vcpu, u64 icpval);
 extern int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq,
                               int level, bool line_status);
 extern void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu);
+extern void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu);
 
 static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu)
 {
@@ -711,6 +712,7 @@ static inline int kvmppc_xive_set_icp(struct kvm_vcpu *vcpu, u64 icpval) { retur
 static inline int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq,
                                      int level, bool line_status) { return -ENODEV; }
 static inline void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu) { }
+static inline void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu) { }
 
 static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu)
        { return 0; }

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 13728495ac6605e493e24165cc456fa55523d253..907963b174e191f840a8a8ec01c3d80e5bb037bf 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3570,6 +3570,8 @@ static int kvmhv_load_hv_regs_and_go(struct kvm_vcpu *vcpu, u64 time_limit,
 
        trap = __kvmhv_vcpu_entry_p9(vcpu);
 
+       kvmppc_xive_pull_vcpu(vcpu);
+
        /* Advance host PURR/SPURR by the amount used by guest */
        purr = mfspr(SPRN_PURR);
        spurr = mfspr(SPRN_SPURR);

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index a8abe79bcb995007824140ac461ac10ea2b62249..55d4d5495f5d076c9e9fc154f250b2045002b020 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1445,6 +1445,11 @@ guest_exit_cont:         /* r9 = vcpu, r12 = trap, r13 = paca */
        bl      kvmhv_accumulate_time
 #endif
 #ifdef CONFIG_KVM_XICS
+       /* If we came in through the P9 short path, xive pull is done in C */
+       lwz     r0, STACK_SLOT_SHORT_PATH(r1)
+       cmpwi   r0, 0
+       bne     1f
+
        /* We are exiting, pull the VP from the XIVE */
        lbz     r0, VCPU_XIVE_PUSHED(r9)
        cmpwi   cr0, r0, 0

diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index e7219b6f5f9a5e98a4e2229d5e66a79792ca53da..741bf1f4387a5ed7b22a13a33ffa9fab70ace474 100644 (file)
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -127,6 +127,37 @@ void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvmppc_xive_push_vcpu);
 
+/*
+ * Pull a vcpu's context from the XIVE on guest exit.
+ * This assumes we are in virtual mode (MMU on)
+ */
+void kvmppc_xive_pull_vcpu(struct kvm_vcpu *vcpu)
+{
+       void __iomem *tima = local_paca->kvm_hstate.xive_tima_virt;
+
+       if (!vcpu->arch.xive_pushed)
+               return;
+
+       /*
+        * Should not have been pushed if there is no tima
+        */
+       if (WARN_ON(!tima))
+               return;
+
+       eieio();
+       /* First load to pull the context, we ignore the value */
+       __raw_readl(tima + TM_SPC_PULL_OS_CTX);
+       /* Second load to recover the context state (Words 0 and 1) */
+       vcpu->arch.xive_saved_state.w01 = __raw_readq(tima + TM_QW1_OS);
+
+       /* Fixup some of the state for the next load */
+       vcpu->arch.xive_saved_state.lsmfb = 0;
+       vcpu->arch.xive_saved_state.ack = 0xff;
+       vcpu->arch.xive_pushed = 0;
+       eieio();
+}
+EXPORT_SYMBOL_GPL(kvmppc_xive_pull_vcpu);
+
 /*
  * This is a simple trigger for a generic XIVE IRQ. This must
  * only be called for interrupts that support a trigger page