This adds basic emulation of the PURR and SPURR registers. We assume
we are emulating a single-threaded core, so these advance at the same
rate as the timebase. A Linux kernel running on a POWER7 expects to
be able to access these registers and is not prepared to handle a
program interrupt on accessing them.
This also adds a very minimal emulation of the DSCR (data stream
control register). Writes are ignored and reads return zero.
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
---
This adds these registers for all CPUs; currently we don't seem to
make the presence or absence of SPRs depend on the PVR, but maybe we
should.
arch/powerpc/include/asm/kvm_book3s.h | 2 ++
arch/powerpc/kvm/book3s_emulate.c | 16 +++++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index ab73800..c568d82 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -81,6 +81,8 @@ struct kvmppc_vcpu_book3s {
u64 sdr1;
u64 hior;
u64 msr_mask;
+ u64 purr_offset;
+ u64 spurr_offset;
#ifdef CONFIG_PPC_BOOK3S_32
u32 vsid_pool[VSID_POOL_SIZE];
u32 vsid_next;
diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index b9a989d..d31a716 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -22,6 +22,7 @@
#include <asm/kvm_book3s.h>
#include <asm/reg.h>
#include <asm/switch_to.h>
+#include <asm/time.h>
#define OP_19_XOP_RFID 18
#define OP_19_XOP_RFI 50
@@ -395,6 +396,12 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
(mfmsr() & MSR_HV))
vcpu->arch.hflags |= BOOK3S_HFLAG_DCBZ32;
break;
+ case SPRN_PURR:
+ to_book3s(vcpu)->purr_offset = spr_val - get_tb();
+ break;
+ case SPRN_SPURR:
+ to_book3s(vcpu)->spurr_offset = spr_val - get_tb();
+ break;
case SPRN_GQR0:
case SPRN_GQR1:
case SPRN_GQR2:
@@ -412,6 +419,7 @@ int kvmppc_core_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
case SPRN_CTRLF:
case SPRN_CTRLT:
case SPRN_L2CR:
+ case SPRN_DSCR:
case SPRN_MMCR0_GEKKO:
case SPRN_MMCR1_GEKKO:
case SPRN_PMC1_GEKKO:
@@ -483,9 +491,15 @@ int kvmppc_core_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
*spr_val = to_book3s(vcpu)->hid[5];
break;
case SPRN_CFAR:
- case SPRN_PURR:
+ case SPRN_DSCR:
*spr_val = 0;
break;
+ case SPRN_PURR:
+ *spr_val = get_tb() + to_book3s(vcpu)->purr_offset;
+ break;
+ case SPRN_SPURR:
+ *spr_val = get_tb() + to_book3s(vcpu)->purr_offset;
+ break;
case SPRN_GQR0:
case SPRN_GQR1:
case SPRN_GQR2:
--
1.7.10.4
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