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KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code 

This is based on a patch by Suraj Jitindar Singh.

This moves the code in book3s_hv_rmhandlers.S that generates an
external, decrementer or privileged doorbell interrupt just before
entering the guest to C code in book3s_hv_builtin.c.  This is to
make future maintenance and modification easier.  The algorithm
expressed in the C code is almost identical to the previous
algorithm.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras 2018-10-08 16:30:50 +11:00 committed by Michael Ellerman
parent 966eba9316
commit f7035ce9f1
4 changed files with 67 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/powerpc/include/asm/kvm_ppc.h
View File

@ -650,6 +650,7 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
unsigned long mfrr);
int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr);
int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr);
void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu);
/*
* Host-side operations we want to set up while running in real

3
arch/powerpc/kvm/book3s_hv.c
View File

@ -730,8 +730,7 @@ static bool kvmppc_doorbell_pending(struct kvm_vcpu *vcpu)
/*
* Ensure that the read of vcore->dpdes comes after the read
* of vcpu->doorbell_request. This barrier matches the
* lwsync in book3s_hv_rmhandlers.S just before the
* fast_guest_return label.
* smb_wmb() in kvmppc_guest_entry_inject().
*/
smp_rmb();
vc = vcpu->arch.vcore;

48
arch/powerpc/kvm/book3s_hv_builtin.c
View File

@ -729,3 +729,51 @@ void kvmhv_p9_restore_lpcr(struct kvm_split_mode *sip)
smp_mb();
local_paca->kvm_hstate.kvm_split_mode = NULL;
}
/*
* Is there a PRIV_DOORBELL pending for the guest (on POWER9)?
* Can we inject a Decrementer or a External interrupt?
*/
void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu)
{
int ext;
unsigned long vec = 0;
unsigned long lpcr;
/* Insert EXTERNAL bit into LPCR at the MER bit position */
ext = (vcpu->arch.pending_exceptions >> BOOK3S_IRQPRIO_EXTERNAL) & 1;
lpcr = mfspr(SPRN_LPCR);
lpcr |= ext << LPCR_MER_SH;
mtspr(SPRN_LPCR, lpcr);
isync();
if (vcpu->arch.shregs.msr & MSR_EE) {
if (ext) {
vec = BOOK3S_INTERRUPT_EXTERNAL;
} else {
long int dec = mfspr(SPRN_DEC);
if (!(lpcr & LPCR_LD))
dec = (int) dec;
if (dec < 0)
vec = BOOK3S_INTERRUPT_DECREMENTER;
}
}
if (vec) {
unsigned long msr, old_msr = vcpu->arch.shregs.msr;
kvmppc_set_srr0(vcpu, kvmppc_get_pc(vcpu));
kvmppc_set_srr1(vcpu, old_msr);
kvmppc_set_pc(vcpu, vec);
msr = vcpu->arch.intr_msr;
if (MSR_TM_ACTIVE(old_msr))
msr |= MSR_TS_S;
vcpu->arch.shregs.msr = msr;
}
if (vcpu->arch.doorbell_request) {
mtspr(SPRN_DPDES, 1);
vcpu->arch.vcore->dpdes = 1;
smp_wmb();
vcpu->arch.doorbell_request = 0;
}
}

70
arch/powerpc/kvm/book3s_hv_rmhandlers.S
View File

@ -1101,13 +1101,20 @@ no_xive:
#endif /* CONFIG_KVM_XICS */
deliver_guest_interrupt:
ld r6, VCPU_CTR(r4)
ld r7, VCPU_XER(r4)
mtctr r6
mtxer r7
kvmppc_cede_reentry: /* r4 = vcpu, r13 = paca */
/* Check if we can deliver an external or decrementer interrupt now */
ld r0, VCPU_PENDING_EXC(r4)
BEGIN_FTR_SECTION
/* On POWER9, also check for emulated doorbell interrupt */
lbz r3, VCPU_DBELL_REQ(r4)
or r0, r0, r3
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
cmpdi r0, 0
beq 71f
mr r3, r4
bl kvmppc_guest_entry_inject_int
ld r4, HSTATE_KVM_VCPU(r13)
71:
ld r10, VCPU_PC(r4)
ld r11, VCPU_MSR(r4)
ld r6, VCPU_SRR0(r4)
@ -1120,53 +1127,10 @@ kvmppc_cede_reentry: /* r4 = vcpu, r13 = paca */
rotldi r11, r11, 1 + MSR_HV_LG
ori r11, r11, MSR_ME
/* Check if we can deliver an external or decrementer interrupt now */
ld r0, VCPU_PENDING_EXC(r4)
rldicl r0, r0, 64 - BOOK3S_IRQPRIO_EXTERNAL, 63
cmpdi cr1, r0, 0
andi. r8, r11, MSR_EE
mfspr r8, SPRN_LPCR
/* Insert EXTERNAL bit into LPCR at the MER bit position */
rldimi r8, r0, LPCR_MER_SH, 63 - LPCR_MER_SH
mtspr SPRN_LPCR, r8
isync
beq 5f
li r0, BOOK3S_INTERRUPT_EXTERNAL
bne cr1, 12f
mfspr r0, SPRN_DEC
BEGIN_FTR_SECTION
/* On POWER9 check whether the guest has large decrementer enabled */
andis. r8, r8, LPCR_LD@h
bne 15f
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
extsw r0, r0
15: cmpdi r0, 0
li r0, BOOK3S_INTERRUPT_DECREMENTER
bge 5f
12: mtspr SPRN_SRR0, r10
mr r10,r0
mtspr SPRN_SRR1, r11
mr r9, r4
bl kvmppc_msr_interrupt
5:
BEGIN_FTR_SECTION
b fast_guest_return
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
/* On POWER9, check for pending doorbell requests */
lbz r0, VCPU_DBELL_REQ(r4)
cmpwi r0, 0
beq fast_guest_return
ld r5, HSTATE_KVM_VCORE(r13)
/* Set DPDES register so the CPU will take a doorbell interrupt */
li r0, 1
mtspr SPRN_DPDES, r0
std r0, VCORE_DPDES(r5)
/* Make sure other cpus see vcore->dpdes set before dbell req clear */
lwsync
/* Clear the pending doorbell request */
li r0, 0
stb r0, VCPU_DBELL_REQ(r4)
ld r6, VCPU_CTR(r4)
ld r7, VCPU_XER(r4)
mtctr r6
mtxer r7
/*
* Required state: