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, 83 insertions, 9 deletions

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index 7e345e00661a..8277264a0bc5 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -107,9 +107,20 @@ static u64 kvmppc_mmu_book3s_64_ea_to_vp(struct kvm_vcpu *vcpu, gva_t eaddr,
 	return kvmppc_slb_calc_vpn(slb, eaddr);
 }
 
+static int mmu_pagesize(int mmu_pg)
+{
+	switch (mmu_pg) {
+	case MMU_PAGE_64K:
+		return 16;
+	case MMU_PAGE_16M:
+		return 24;
+	}
+	return 12;
+}
+
 static int kvmppc_mmu_book3s_64_get_pagesize(struct kvmppc_slb *slbe)
 {
-	return slbe->large ? 24 : 12;
+	return mmu_pagesize(slbe->base_page_size);
 }
 
 static u32 kvmppc_mmu_book3s_64_get_page(struct kvmppc_slb *slbe, gva_t eaddr)
@@ -166,14 +177,34 @@ static u64 kvmppc_mmu_book3s_64_get_avpn(struct kvmppc_slb *slbe, gva_t eaddr)
 	avpn = kvmppc_mmu_book3s_64_get_page(slbe, eaddr);
 	avpn |= slbe->vsid << (kvmppc_slb_sid_shift(slbe) - p);
 
-	if (p < 24)
-		avpn >>= ((80 - p) - 56) - 8;
+	if (p < 16)
+		avpn >>= ((80 - p) - 56) - 8;	/* 16 - p */
 	else
-		avpn <<= 8;
+		avpn <<= p - 16;
 
 	return avpn;
 }
 
+/*
+ * Return page size encoded in the second word of a HPTE, or
+ * -1 for an invalid encoding for the base page size indicated by
+ * the SLB entry.  This doesn't handle mixed pagesize segments yet.
+ */
+static int decode_pagesize(struct kvmppc_slb *slbe, u64 r)
+{
+	switch (slbe->base_page_size) {
+	case MMU_PAGE_64K:
+		if ((r & 0xf000) == 0x1000)
+			return MMU_PAGE_64K;
+		break;
+	case MMU_PAGE_16M:
+		if ((r & 0xff000) == 0)
+			return MMU_PAGE_16M;
+		break;
+	}
+	return -1;
+}
+
 static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 				struct kvmppc_pte *gpte, bool data)
 {
@@ -189,6 +220,7 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 	u8 pp, key = 0;
 	bool found = false;
 	bool second = false;
+	int pgsize;
 	ulong mp_ea = vcpu->arch.magic_page_ea;
 
 	/* Magic page override */
@@ -202,6 +234,7 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 		gpte->may_execute = true;
 		gpte->may_read = true;
 		gpte->may_write = true;
+		gpte->page_size = MMU_PAGE_4K;
 
 		return 0;
 	}
@@ -222,6 +255,8 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
 	v_mask = SLB_VSID_B | HPTE_V_AVPN | HPTE_V_LARGE | HPTE_V_VALID |
 		HPTE_V_SECONDARY;
 
+	pgsize = slbe->large ? MMU_PAGE_16M : MMU_PAGE_4K;
+
 do_second:
 	ptegp = kvmppc_mmu_book3s_64_get_pteg(vcpu_book3s, slbe, eaddr, second);
 	if (kvm_is_error_hva(ptegp))
@@ -240,6 +275,13 @@ do_second:
 	for (i=0; i<16; i+=2) {
 		/* Check all relevant fields of 1st dword */
 		if ((pteg[i] & v_mask) == v_val) {
+			/* If large page bit is set, check pgsize encoding */
+			if (slbe->large &&
+			    (vcpu->arch.hflags & BOOK3S_HFLAG_MULTI_PGSIZE)) {
+				pgsize = decode_pagesize(slbe, pteg[i+1]);
+				if (pgsize < 0)
+					continue;
+			}
 			found = true;
 			break;
 		}
@@ -256,13 +298,13 @@ do_second:
 	v = pteg[i];
 	r = pteg[i+1];
 	pp = (r & HPTE_R_PP) | key;
-	eaddr_mask = 0xFFF;
 
 	gpte->eaddr = eaddr;
 	gpte->vpage = kvmppc_mmu_book3s_64_ea_to_vp(vcpu, eaddr, data);
-	if (slbe->large)
-		eaddr_mask = 0xFFFFFF;
+
+	eaddr_mask = (1ull << mmu_pagesize(pgsize)) - 1;
 	gpte->raddr = (r & HPTE_R_RPN & ~eaddr_mask) | (eaddr & eaddr_mask);
+	gpte->page_size = pgsize;
 	gpte->may_execute = ((r & HPTE_R_N) ? false : true);
 	gpte->may_read = false;
 	gpte->may_write = false;
@@ -345,6 +387,21 @@ static void kvmppc_mmu_book3s_64_slbmte(struct kvm_vcpu *vcpu, u64 rs, u64 rb)
 	slbe->nx    = (rs & SLB_VSID_N) ? 1 : 0;
 	slbe->class = (rs & SLB_VSID_C) ? 1 : 0;
 
+	slbe->base_page_size = MMU_PAGE_4K;
+	if (slbe->large) {
+		if (vcpu->arch.hflags & BOOK3S_HFLAG_MULTI_PGSIZE) {
+			switch (rs & SLB_VSID_LP) {
+			case SLB_VSID_LP_00:
+				slbe->base_page_size = MMU_PAGE_16M;
+				break;
+			case SLB_VSID_LP_01:
+				slbe->base_page_size = MMU_PAGE_64K;
+				break;
+			}
+		} else
+			slbe->base_page_size = MMU_PAGE_16M;
+	}
+
 	slbe->orige = rb & (ESID_MASK | SLB_ESID_V);
 	slbe->origv = rs;
 
@@ -463,8 +520,25 @@ static void kvmppc_mmu_book3s_64_tlbie(struct kvm_vcpu *vcpu, ulong va,
 
 	dprintk("KVM MMU: tlbie(0x%lx)\n", va);
 
-	if (large)
-		mask = 0xFFFFFF000ULL;
+	/*
+	 * The tlbie instruction changed behaviour starting with
+	 * POWER6.  POWER6 and later don't have the large page flag
+	 * in the instruction but in the RB value, along with bits
+	 * indicating page and segment sizes.
+	 */
+	if (vcpu->arch.hflags & BOOK3S_HFLAG_NEW_TLBIE) {
+		/* POWER6 or later */
+		if (va & 1) {		/* L bit */
+			if ((va & 0xf000) == 0x1000)
+				mask = 0xFFFFFFFF0ULL;	/* 64k page */
+			else
+				mask = 0xFFFFFF000ULL;	/* 16M page */
+		}
+	} else {
+		/* older processors, e.g. PPC970 */
+		if (large)
+			mask = 0xFFFFFF000ULL;
+	}
 	kvmppc_mmu_pte_vflush(vcpu, va >> 12, mask);
 }