KVM: PPC: Book3S PR: Allow guest to use 64k pages

This adds the code to interpret 64k HPTEs in the guest hashed page
table (HPT), 64k SLB entries, and to tell the guest about 64k pages
in kvm_vm_ioctl_get_smmu_info().  Guest 64k pages are still shadowed
by 4k pages.

This also adds another hash table to the four we have already in
book3s_mmu_hpte.c to allow us to find all the PTEs that we have
instantiated that match a given 64k guest page.

The tlbie instruction changed starting with POWER6 to use a bit in
the RB operand to indicate large page invalidations, and to use other
RB bits to indicate the base and actual page sizes and the segment
size.  64k pages came in slightly earlier, with POWER5++.
We use one bit in vcpu->arch.hflags to indicate that the emulated
cpu supports 64k pages, and another to indicate that it has the new
tlbie definition.

The KVM_PPC_GET_SMMU_INFO ioctl presents a bit of a problem, because
the MMU capabilities depend on which CPU model we're emulating, but it
is a VM ioctl not a VCPU ioctl and therefore doesn't get passed a VCPU
fd.  In addition, commonly-used userspace (QEMU) calls it before
setting the PVR for any VCPU.  Therefore, as a best effort we look at
the first vcpu in the VM and return 64k pages or not depending on its
capabilities.  We also make the PVR default to the host PVR on recent
CPUs that support 1TB segments (and therefore multiple page sizes as
well) so that KVM_PPC_GET_SMMU_INFO will include 64k page and 1TB
segment support on those CPUs.

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

1 files changed, 52 insertions, 6 deletions

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 228a9baffd9e..6cc99583ed39 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -306,6 +306,23 @@ void kvmppc_set_pvr(struct kvm_vcpu *vcpu, u32 pvr)
         if (!strcmp(cur_cpu_spec->platform, "ppc-cell-be"))
                 to_book3s(vcpu)->msr_mask &= ~(MSR_FE0 | MSR_FE1);
 
+        /*
+         * If they're asking for POWER6 or later, set the flag
+         * indicating that we can do multiple large page sizes
+         * and 1TB segments.
+         * Also set the flag that indicates that tlbie has the large
+         * page bit in the RB operand instead of the instruction.
+         */
+        switch (PVR_VER(pvr)) {
+        case PVR_POWER6:
+        case PVR_POWER7:
+        case PVR_POWER7p:
+        case PVR_POWER8:
+                vcpu->arch.hflags |= BOOK3S_HFLAG_MULTI_PGSIZE |
+                        BOOK3S_HFLAG_NEW_TLBIE;
+                break;
+        }
+
 #ifdef CONFIG_PPC_BOOK3S_32
         /* 32 bit Book3S always has 32 byte dcbz */
         vcpu->arch.hflags |= BOOK3S_HFLAG_DCBZ32;
@@ -1130,8 +1147,14 @@ struct kvm_vcpu *kvmppc_core_vcpu_create(struct kvm *kvm, unsigned int id)
         vcpu->arch.shared = (void *)(p + PAGE_SIZE - 4096);
 
 #ifdef CONFIG_PPC_BOOK3S_64
-        /* default to book3s_64 (970fx) */
+        /*
+         * Default to the same as the host if we're on sufficiently
+         * recent machine that we have 1TB segments;
+         * otherwise default to PPC970FX.
+         */
         vcpu->arch.pvr = 0x3C0301;
+        if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
+                vcpu->arch.pvr = mfspr(SPRN_PVR);
 #else
         /* default to book3s_32 (750) */
         vcpu->arch.pvr = 0x84202;
@@ -1317,7 +1340,10 @@ out:
 #ifdef CONFIG_PPC64
 int kvm_vm_ioctl_get_smmu_info(struct kvm *kvm, struct kvm_ppc_smmu_info *info)
 {
-        info->flags = KVM_PPC_1T_SEGMENTS;
+        long int i;
+        struct kvm_vcpu *vcpu;
+
+        info->flags = 0;
 
         /* SLB is always 64 entries */
         info->slb_size = 64;
@@ -1328,11 +1354,31 @@ int kvm_vm_ioctl_get_smmu_info(struct kvm *kvm, struct kvm_ppc_smmu_info *info)
         info->sps[0].enc[0].page_shift = 12;
         info->sps[0].enc[0].pte_enc = 0;
 
+        /*
+         * 64k large page size.
+         * We only want to put this in if the CPUs we're emulating
+         * support it, but unfortunately we don't have a vcpu easily
+         * to hand here to test.  Just pick the first vcpu, and if
+         * that doesn't exist yet, report the minimum capability,
+         * i.e., no 64k pages.
+         * 1T segment support goes along with 64k pages.
+         */
+        i = 1;
+        vcpu = kvm_get_vcpu(kvm, 0);
+        if (vcpu && (vcpu->arch.hflags & BOOK3S_HFLAG_MULTI_PGSIZE)) {
+                info->flags = KVM_PPC_1T_SEGMENTS;
+                info->sps[i].page_shift = 16;
+                info->sps[i].slb_enc = SLB_VSID_L | SLB_VSID_LP_01;
+                info->sps[i].enc[0].page_shift = 16;
+                info->sps[i].enc[0].pte_enc = 1;
+                ++i;
+        }
+
         /* Standard 16M large page size segment */
-        info->sps[1].page_shift = 24;
-        info->sps[1].slb_enc = SLB_VSID_L;
-        info->sps[1].enc[0].page_shift = 24;
-        info->sps[1].enc[0].pte_enc = 0;
+        info->sps[i].page_shift = 24;
+        info->sps[i].slb_enc = SLB_VSID_L;
+        info->sps[i].enc[0].page_shift = 24;
+        info->sps[i].enc[0].pte_enc = 0;
 
         return 0;
 }