KVM: PPC: Book3S HV: Translate kvmhv_commence_exit to C

This replaces the assembler code for kvmhv_commence_exit() with C code
in book3s_hv_builtin.c.  It also moves the IPI sending code that was
in book3s_hv_rm_xics.c into a new kvmhv_rm_send_ipi() function so it
can be used by kvmhv_commence_exit() as well as icp_rm_set_vcpu_irq().

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

4 files changed, 75 insertions, 68 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 869c53fe02cd..2b84e485a181 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -438,6 +438,8 @@ static inline struct kvm_memslots *kvm_memslots_raw(struct kvm *kvm)
 
 extern void kvmppc_mmu_debugfs_init(struct kvm *kvm);
 
+extern void kvmhv_rm_send_ipi(int cpu);
+
 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
 
 #endif /* __ASM_KVM_BOOK3S_64_H__ */
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 275425142bb7..c42aa55b885f 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -22,6 +22,7 @@
 #include <asm/kvm_ppc.h>
 #include <asm/kvm_book3s.h>
 #include <asm/archrandom.h>
+#include <asm/xics.h>
 
 #define KVM_CMA_CHUNK_ORDER     18
 
@@ -184,3 +185,65 @@ long kvmppc_h_random(struct kvm_vcpu *vcpu)
 
         return H_HARDWARE;
 }
+
+static inline void rm_writeb(unsigned long paddr, u8 val)
+{
+        __asm__ __volatile__("stbcix %0,0,%1"
+                : : "r" (val), "r" (paddr) : "memory");
+}
+
+/*
+ * Send an interrupt to another CPU.
+ * This can only be called in real mode.
+ * The caller needs to include any barrier needed to order writes
+ * to memory vs. the IPI/message.
+ */
+void kvmhv_rm_send_ipi(int cpu)
+{
+        unsigned long xics_phys;
+
+        /* Poke the target */
+        xics_phys = paca[cpu].kvm_hstate.xics_phys;
+        rm_writeb(xics_phys + XICS_MFRR, IPI_PRIORITY);
+}
+
+/*
+ * The following functions are called from the assembly code
+ * in book3s_hv_rmhandlers.S.
+ */
+static void kvmhv_interrupt_vcore(struct kvmppc_vcore *vc, int active)
+{
+        int cpu = vc->pcpu;
+
+        /* Order setting of exit map vs. msgsnd/IPI */
+        smp_mb();
+        for (; active; active >>= 1, ++cpu)
+                if (active & 1)
+                        kvmhv_rm_send_ipi(cpu);
+}
+
+void kvmhv_commence_exit(int trap)
+{
+        struct kvmppc_vcore *vc = local_paca->kvm_hstate.kvm_vcore;
+        int ptid = local_paca->kvm_hstate.ptid;
+        int me, ee;
+
+        /* Set our bit in the threads-exiting-guest map in the 0xff00
+           bits of vcore->entry_exit_map */
+        me = 0x100 << ptid;
+        do {
+                ee = vc->entry_exit_map;
+        } while (cmpxchg(&vc->entry_exit_map, ee, ee | me) != ee);
+
+        /* Are we the first here? */
+        if ((ee >> 8) != 0)
+                return;
+
+        /*
+         * Trigger the other threads in this vcore to exit the guest.
+         * If this is a hypervisor decrementer interrupt then they
+         * will be already on their way out of the guest.
+         */
+        if (trap != BOOK3S_INTERRUPT_HV_DECREMENTER)
+                kvmhv_interrupt_vcore(vc, ee & ~(1 << ptid));
+}
diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index 6dded8c75234..00e45b6d4f24 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -26,12 +26,6 @@
 static void icp_rm_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
                             u32 new_irq);
 
-static inline void rm_writeb(unsigned long paddr, u8 val)
-{
-        __asm__ __volatile__("sync; stbcix %0,0,%1"
-                : : "r" (val), "r" (paddr) : "memory");
-}
-
 /* -- ICS routines -- */
 static void ics_rm_check_resend(struct kvmppc_xics *xics,
                                 struct kvmppc_ics *ics, struct kvmppc_icp *icp)
@@ -60,7 +54,6 @@ static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu,
                                 struct kvm_vcpu *this_vcpu)
 {
         struct kvmppc_icp *this_icp = this_vcpu->arch.icp;
-        unsigned long xics_phys;
         int cpu;
 
         /* Mark the target VCPU as having an interrupt pending */
@@ -83,9 +76,8 @@ static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu,
         /* In SMT cpu will always point to thread 0, we adjust it */
         cpu += vcpu->arch.ptid;
 
-        /* Not too hard, then poke the target */
-        xics_phys = paca[cpu].kvm_hstate.xics_phys;
-        rm_writeb(xics_phys + XICS_MFRR, IPI_PRIORITY);
+        smp_mb();
+        kvmhv_rm_send_ipi(cpu);
 }
 
 static void icp_rm_clr_vcpu_irq(struct kvm_vcpu *vcpu)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 3f6fd78cccd2..fcf3a617cc8a 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -264,7 +264,11 @@ kvm_novcpu_exit:
         addi    r3, r4, VCPU_TB_RMEXIT
         bl      kvmhv_accumulate_time
 #endif
-13:     bl      kvmhv_commence_exit
+13:     mr      r3, r12
+        stw     r12, 112-4(r1)
+        bl      kvmhv_commence_exit
+        nop
+        lwz     r12, 112-4(r1)
         b       kvmhv_switch_to_host
 
 /*
@@ -1161,6 +1165,9 @@ mc_cont:
 
         /* Increment exit count, poke other threads to exit */
         bl      kvmhv_commence_exit
+        nop
+        ld      r9, HSTATE_KVM_VCPU(r13)
+        lwz     r12, VCPU_TRAP(r9)
 
         /* Save guest CTRL register, set runlatch to 1 */
         mfspr   r6,SPRN_CTRLF
@@ -1614,63 +1621,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
         mtlr    r0
         blr
 
-kvmhv_commence_exit:            /* r12 = trap, r13 = paca, doesn't trash r9 */
-        mflr    r0
-        std     r0, PPC_LR_STKOFF(r1)
-        stdu    r1, -PPC_MIN_STKFRM(r1)
-
-        /* Set our bit in the threads-exiting-guest map in the 0xff00
-           bits of vcore->entry_exit_map */
-        ld      r5, HSTATE_KVM_VCORE(r13)
-        lbz     r4, HSTATE_PTID(r13)
-        li      r7, 0x100
-        sld     r7, r7, r4
-        addi    r6, r5, VCORE_ENTRY_EXIT
-41:     lwarx   r3, 0, r6
-        or      r0, r3, r7
-        stwcx.  r0, 0, r6
-        bne     41b
-        isync           /* order stwcx. vs. reading napping_threads */
-
-        /*
-         * At this point we have an interrupt that we have to pass
-         * up to the kernel or qemu; we can't handle it in real mode.
-         * Thus we have to do a partition switch, so we have to
-         * collect the other threads, if we are the first thread
-         * to take an interrupt.  To do this, we send a message or
-         * IPI to all the threads that have their bit set in the entry
-         * map in vcore->entry_exit_map (other than ourselves).
-         * However, we don't need to bother if this is an HDEC
-         * interrupt, since the other threads will already be on their
-         * way here in that case.
-         */
-        cmpwi   r3,0x100        /* Are we the first here? */
-        bge     43f
-        cmpwi   r12,BOOK3S_INTERRUPT_HV_DECREMENTER
-        beq     43f
-
-        srwi    r0,r7,8
-        andc.   r3,r3,r0                /* no sense IPI'ing ourselves */
-        beq     43f
-        /* Order entry/exit update vs. IPIs */
-        sync
-        mulli   r4,r4,PACA_SIZE         /* get paca for thread 0 */
-        subf    r6,r4,r13
-42:     andi.   r0,r3,1
-        beq     44f
-        ld      r8,HSTATE_XICS_PHYS(r6) /* get thread's XICS reg addr */
-        li      r0,IPI_PRIORITY
-        li      r7,XICS_MFRR
-        stbcix  r0,r7,r8                /* trigger the IPI */
-44:     srdi.   r3,r3,1
-        addi    r6,r6,PACA_SIZE
-        bne     42b
-
-43:     ld      r0, PPC_MIN_STKFRM+PPC_LR_STKOFF(r1)
-        addi    r1, r1, PPC_MIN_STKFRM
-        mtlr    r0
-        blr
-
 /*
  * Check whether an HDSI is an HPTE not found fault or something else.
  * If it is an HPTE not found fault that is due to the guest accessing