[6/6] KVM: PPC: Book3S PR: Expose TM registers

Commit Message

Alexander Graf May 20, 2014, 11:49 a.m. UTC

On 20.05.2014, at 11:59, Paul Mackerras <[e-mail]> wrote:

> On Mon, May 19, 2014 at 03:09:07PM +0200, Alexander Graf wrote:
>> 
>> On 17.05.14 08:20, Paul Mackerras wrote:
>>> On Tue, Apr 29, 2014 at 06:17:42PM +0200, Alexander Graf wrote:
>>>> POWER8 introduces transactional memory which brings along a number of new
>>>> registers and MSR bits.
>>>> 
>>>> Implementing all of those is a pretty big headache, so for now let's at least
>>>> emulate enough to make Linux's context switching code happy.
>>> [snip]
>>> 
>>>> -	if (!(vcpu->arch.fscr & (1ULL << fac))) {
>>>> +	/* We get TM interrupts only when EBB is disabled? Sigh. */
>>> This comment doesn't make sense to me.  Not every reason code reported
>>> in the high bits of FSCR corresponds directly to an enable bit in
>>> FSCR.  In fact, of the 7 defined reason codes in POWER8, only three
>>> correspond to an enable bit...
>> 
>> Is there any documentation on which relate to what?
> 
> Yes, Power ISA v2.07 book 3S section 6.2.10 describes the FSCR enable
> bits and the interruption cause field.  There are 6 cause values
> defined, of which 3 correspond to enable bits in the FSCR, and the
> other 3 correspond to things enabled/disabled in MMCR0 (usermode PMC
> anb BHRB access) or MSR (TM stuff).

I see. How's this?

Alex

commit a8e53f5f5e6c5d99363ad0d695a9ee520e1d262d
Author: Alexander Graf <[e-mail]>
Date:   Tue Apr 29 17:54:40 2014 +0200

    KVM: PPC: Book3S PR: Expose TM registers

    POWER8 introduces transactional memory which brings along a number of new
    registers and MSR bits.

    Implementing all of those is a pretty big headache, so for now let's at least
    emulate enough to make Linux's context switching code happy.

    Signed-off-by: Alexander Graf <[e-mail]>

    ---

    v1 -> v2:

      - move to book3s_64 only section
      - restrict to CONFIG_PPC_TRANSACTIONAL_MEM

    v2 -> v3:

      - check MSR.TM for TM enablement inside the guest

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Patch

diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c
index e1165ba..9bdff15 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -451,6 +451,17 @@  int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
 	case SPRN_EBBRR:
 		vcpu->arch.ebbrr = spr_val;
 		break;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	case SPRN_TFHAR:
+		vcpu->arch.tfhar = spr_val;
+		break;
+	case SPRN_TEXASR:
+		vcpu->arch.texasr = spr_val;
+		break;
+	case SPRN_TFIAR:
+		vcpu->arch.tfiar = spr_val;
+		break;
+#endif
 #endif
 	case SPRN_ICTC:
 	case SPRN_THRM1:
@@ -572,6 +583,17 @@  int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val
 	case SPRN_EBBRR:
 		*spr_val = vcpu->arch.ebbrr;
 		break;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	case SPRN_TFHAR:
+		*spr_val = vcpu->arch.tfhar;
+		break;
+	case SPRN_TEXASR:
+		*spr_val = vcpu->arch.texasr;
+		break;
+	case SPRN_TFIAR:
+		*spr_val = vcpu->arch.tfiar;
+		break;
+#endif
 #endif
 	case SPRN_THRM1:
 	case SPRN_THRM2:
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 7d27a95..23367a7 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -794,9 +794,27 @@  static void kvmppc_emulate_fac(struct kvm_vcpu *vcpu, ulong fac)
 /* Enable facilities (TAR, EBB, DSCR) for the guest */
 static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac)
 {
+	bool guest_fac_enabled;
 	BUG_ON(!cpu_has_feature(CPU_FTR_ARCH_207S));

-	if (!(vcpu->arch.fscr & (1ULL << fac))) {
+	/*
+	 * Not every facility is enabled by FSCR bits, check whether the
+	 * guest has this facility enabled at all.
+	 */
+	switch (fac) {
+	case FSCR_TAR_LG:
+	case FSCR_EBB_LG:
+		guest_fac_enabled = (vcpu->arch.fscr & (1ULL << fac));
+		break;
+	case FSCR_TM_LG:
+		guest_fac_enabled = kvmppc_get_msr(vcpu) & MSR_TM;
+		break;
+	default:
+		guest_fac_enabled = false;
+		break;
+	}
+
+	if (!guest_fac_enabled) {
 		/* Facility not enabled by the guest */
 		kvmppc_trigger_fac_interrupt(vcpu, fac);
 		return RESUME_GUEST;--