KVM: PPC: Handle some PAPR hcalls in the kernel

This adds the infrastructure for handling PAPR hcalls in the kernel,
either early in the guest exit path while we are still in real mode,
or later once the MMU has been turned back on and we are in the full
kernel context.  The advantage of handling hcalls in real mode if
possible is that we avoid two partition switches -- and this will
become more important when we support SMT4 guests, since a partition
switch means we have to pull all of the threads in the core out of
the guest.  The disadvantage is that we can only access the kernel
linear mapping, not anything vmalloced or ioremapped, since the MMU
is off.

This also adds code to handle the following hcalls in real mode:

H_ENTER       Add an HPTE to the hashed page table
H_REMOVE      Remove an HPTE from the hashed page table
H_READ        Read HPTEs from the hashed page table
H_PROTECT     Change the protection bits in an HPTE
H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table
H_SET_DABR    Set the data address breakpoint register

Plus code to handle the following hcalls in the kernel:

H_CEDE        Idle the vcpu until an interrupt or H_PROD hcall arrives
H_PROD        Wake up a ceded vcpu
H_REGISTER_VPA Register a virtual processor area (VPA)

The code that runs in real mode has to be in the base kernel, not in
the module, if KVM is compiled as a module.  The real-mode code can
only access the kernel linear mapping, not vmalloc or ioremap space.

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

1 files changed, 368 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
new file mode 100644
index 000000000000..edb0aae901a3
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -0,0 +1,368 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * Copyright 2010-2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/hugetlb.h>
+
+#include <asm/tlbflush.h>
+#include <asm/kvm_ppc.h>
+#include <asm/kvm_book3s.h>
+#include <asm/mmu-hash64.h>
+#include <asm/hvcall.h>
+#include <asm/synch.h>
+#include <asm/ppc-opcode.h>
+
+/* For now use fixed-size 16MB page table */
+#define HPT_ORDER	24
+#define HPT_NPTEG	(1ul << (HPT_ORDER - 7))	/* 128B per pteg */
+#define HPT_HASH_MASK	(HPT_NPTEG - 1)
+
+#define HPTE_V_HVLOCK	0x40UL
+
+static inline long lock_hpte(unsigned long *hpte, unsigned long bits)
+{
+	unsigned long tmp, old;
+
+	asm volatile("	ldarx	%0,0,%2\n"
+		     "	and.	%1,%0,%3\n"
+		     "	bne	2f\n"
+		     "	ori	%0,%0,%4\n"
+		     "  stdcx.	%0,0,%2\n"
+		     "	beq+	2f\n"
+		     "	li	%1,%3\n"
+		     "2:	isync"
+		     : "=&r" (tmp), "=&r" (old)
+		     : "r" (hpte), "r" (bits), "i" (HPTE_V_HVLOCK)
+		     : "cc", "memory");
+	return old == 0;
+}
+
+long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
+		    long pte_index, unsigned long pteh, unsigned long ptel)
+{
+	unsigned long porder;
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long i, lpn, pa;
+	unsigned long *hpte;
+
+	/* only handle 4k, 64k and 16M pages for now */
+	porder = 12;
+	if (pteh & HPTE_V_LARGE) {
+		if ((ptel & 0xf000) == 0x1000) {
+			/* 64k page */
+			porder = 16;
+		} else if ((ptel & 0xff000) == 0) {
+			/* 16M page */
+			porder = 24;
+			/* lowest AVA bit must be 0 for 16M pages */
+			if (pteh & 0x80)
+				return H_PARAMETER;
+		} else
+			return H_PARAMETER;
+	}
+	lpn = (ptel & HPTE_R_RPN) >> kvm->arch.ram_porder;
+	if (lpn >= kvm->arch.ram_npages || porder > kvm->arch.ram_porder)
+		return H_PARAMETER;
+	pa = kvm->arch.ram_pginfo[lpn].pfn << PAGE_SHIFT;
+	if (!pa)
+		return H_PARAMETER;
+	/* Check WIMG */
+	if ((ptel & HPTE_R_WIMG) != HPTE_R_M &&
+	    (ptel & HPTE_R_WIMG) != (HPTE_R_W | HPTE_R_I | HPTE_R_M))
+		return H_PARAMETER;
+	pteh &= ~0x60UL;
+	ptel &= ~(HPTE_R_PP0 - kvm->arch.ram_psize);
+	ptel |= pa;
+	if (pte_index >= (HPT_NPTEG << 3))
+		return H_PARAMETER;
+	if (likely((flags & H_EXACT) == 0)) {
+		pte_index &= ~7UL;
+		hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+		for (i = 0; ; ++i) {
+			if (i == 8)
+				return H_PTEG_FULL;
+			if ((*hpte & HPTE_V_VALID) == 0 &&
+			    lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
+				break;
+			hpte += 2;
+		}
+	} else {
+		i = 0;
+		hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+		if (!lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
+			return H_PTEG_FULL;
+	}
+	hpte[1] = ptel;
+	eieio();
+	hpte[0] = pteh;
+	asm volatile("ptesync" : : : "memory");
+	atomic_inc(&kvm->arch.ram_pginfo[lpn].refcnt);
+	vcpu->arch.gpr[4] = pte_index + i;
+	return H_SUCCESS;
+}
+
+static unsigned long compute_tlbie_rb(unsigned long v, unsigned long r,
+				      unsigned long pte_index)
+{
+	unsigned long rb, va_low;
+
+	rb = (v & ~0x7fUL) << 16;		/* AVA field */
+	va_low = pte_index >> 3;
+	if (v & HPTE_V_SECONDARY)
+		va_low = ~va_low;
+	/* xor vsid from AVA */
+	if (!(v & HPTE_V_1TB_SEG))
+		va_low ^= v >> 12;
+	else
+		va_low ^= v >> 24;
+	va_low &= 0x7ff;
+	if (v & HPTE_V_LARGE) {
+		rb |= 1;			/* L field */
+		if (r & 0xff000) {
+			/* non-16MB large page, must be 64k */
+			/* (masks depend on page size) */
+			rb |= 0x1000;		/* page encoding in LP field */
+			rb |= (va_low & 0x7f) << 16; /* 7b of VA in AVA/LP field */
+			rb |= (va_low & 0xfe);	/* AVAL field (P7 doesn't seem to care) */
+		}
+	} else {
+		/* 4kB page */
+		rb |= (va_low & 0x7ff) << 12;	/* remaining 11b of VA */
+	}
+	rb |= (v >> 54) & 0x300;		/* B field */
+	return rb;
+}
+
+#define LOCK_TOKEN	(*(u32 *)(&get_paca()->lock_token))
+
+static inline int try_lock_tlbie(unsigned int *lock)
+{
+	unsigned int tmp, old;
+	unsigned int token = LOCK_TOKEN;
+
+	asm volatile("1:lwarx	%1,0,%2\n"
+		     "	cmpwi	cr0,%1,0\n"
+		     "	bne	2f\n"
+		     "  stwcx.	%3,0,%2\n"
+		     "	bne-	1b\n"
+		     "  isync\n"
+		     "2:"
+		     : "=&r" (tmp), "=&r" (old)
+		     : "r" (lock), "r" (token)
+		     : "cc", "memory");
+	return old == 0;
+}
+
+long kvmppc_h_remove(struct kvm_vcpu *vcpu, unsigned long flags,
+		     unsigned long pte_index, unsigned long avpn,
+		     unsigned long va)
+{
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long *hpte;
+	unsigned long v, r, rb;
+
+	if (pte_index >= (HPT_NPTEG << 3))
+		return H_PARAMETER;
+	hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+	while (!lock_hpte(hpte, HPTE_V_HVLOCK))
+		cpu_relax();
+	if ((hpte[0] & HPTE_V_VALID) == 0 ||
+	    ((flags & H_AVPN) && (hpte[0] & ~0x7fUL) != avpn) ||
+	    ((flags & H_ANDCOND) && (hpte[0] & avpn) != 0)) {
+		hpte[0] &= ~HPTE_V_HVLOCK;
+		return H_NOT_FOUND;
+	}
+	if (atomic_read(&kvm->online_vcpus) == 1)
+		flags |= H_LOCAL;
+	vcpu->arch.gpr[4] = v = hpte[0] & ~HPTE_V_HVLOCK;
+	vcpu->arch.gpr[5] = r = hpte[1];
+	rb = compute_tlbie_rb(v, r, pte_index);
+	hpte[0] = 0;
+	if (!(flags & H_LOCAL)) {
+		while(!try_lock_tlbie(&kvm->arch.tlbie_lock))
+			cpu_relax();
+		asm volatile("ptesync" : : : "memory");
+		asm volatile(PPC_TLBIE(%1,%0)"; eieio; tlbsync"
+			     : : "r" (rb), "r" (kvm->arch.lpid));
+		asm volatile("ptesync" : : : "memory");
+		kvm->arch.tlbie_lock = 0;
+	} else {
+		asm volatile("ptesync" : : : "memory");
+		asm volatile("tlbiel %0" : : "r" (rb));
+		asm volatile("ptesync" : : : "memory");
+	}
+	return H_SUCCESS;
+}
+
+long kvmppc_h_bulk_remove(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long *args = &vcpu->arch.gpr[4];
+	unsigned long *hp, tlbrb[4];
+	long int i, found;
+	long int n_inval = 0;
+	unsigned long flags, req, pte_index;
+	long int local = 0;
+	long int ret = H_SUCCESS;
+
+	if (atomic_read(&kvm->online_vcpus) == 1)
+		local = 1;
+	for (i = 0; i < 4; ++i) {
+		pte_index = args[i * 2];
+		flags = pte_index >> 56;
+		pte_index &= ((1ul << 56) - 1);
+		req = flags >> 6;
+		flags &= 3;
+		if (req == 3)
+			break;
+		if (req != 1 || flags == 3 ||
+		    pte_index >= (HPT_NPTEG << 3)) {
+			/* parameter error */
+			args[i * 2] = ((0xa0 | flags) << 56) + pte_index;
+			ret = H_PARAMETER;
+			break;
+		}
+		hp = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+		while (!lock_hpte(hp, HPTE_V_HVLOCK))
+			cpu_relax();
+		found = 0;
+		if (hp[0] & HPTE_V_VALID) {
+			switch (flags & 3) {
+			case 0:		/* absolute */
+				found = 1;
+				break;
+			case 1:		/* andcond */
+				if (!(hp[0] & args[i * 2 + 1]))
+					found = 1;
+				break;
+			case 2:		/* AVPN */
+				if ((hp[0] & ~0x7fUL) == args[i * 2 + 1])
+					found = 1;
+				break;
+			}
+		}
+		if (!found) {
+			hp[0] &= ~HPTE_V_HVLOCK;
+			args[i * 2] = ((0x90 | flags) << 56) + pte_index;
+			continue;
+		}
+		/* insert R and C bits from PTE */
+		flags |= (hp[1] >> 5) & 0x0c;
+		args[i * 2] = ((0x80 | flags) << 56) + pte_index;
+		tlbrb[n_inval++] = compute_tlbie_rb(hp[0], hp[1], pte_index);
+		hp[0] = 0;
+	}
+	if (n_inval == 0)
+		return ret;
+
+	if (!local) {
+		while(!try_lock_tlbie(&kvm->arch.tlbie_lock))
+			cpu_relax();
+		asm volatile("ptesync" : : : "memory");
+		for (i = 0; i < n_inval; ++i)
+			asm volatile(PPC_TLBIE(%1,%0)
+				     : : "r" (tlbrb[i]), "r" (kvm->arch.lpid));
+		asm volatile("eieio; tlbsync; ptesync" : : : "memory");
+		kvm->arch.tlbie_lock = 0;
+	} else {
+		asm volatile("ptesync" : : : "memory");
+		for (i = 0; i < n_inval; ++i)
+			asm volatile("tlbiel %0" : : "r" (tlbrb[i]));
+		asm volatile("ptesync" : : : "memory");
+	}
+	return ret;
+}
+
+long kvmppc_h_protect(struct kvm_vcpu *vcpu, unsigned long flags,
+		      unsigned long pte_index, unsigned long avpn,
+		      unsigned long va)
+{
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long *hpte;
+	unsigned long v, r, rb;
+
+	if (pte_index >= (HPT_NPTEG << 3))
+		return H_PARAMETER;
+	hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+	while (!lock_hpte(hpte, HPTE_V_HVLOCK))
+		cpu_relax();
+	if ((hpte[0] & HPTE_V_VALID) == 0 ||
+	    ((flags & H_AVPN) && (hpte[0] & ~0x7fUL) != avpn)) {
+		hpte[0] &= ~HPTE_V_HVLOCK;
+		return H_NOT_FOUND;
+	}
+	if (atomic_read(&kvm->online_vcpus) == 1)
+		flags |= H_LOCAL;
+	v = hpte[0];
+	r = hpte[1] & ~(HPTE_R_PP0 | HPTE_R_PP | HPTE_R_N |
+			HPTE_R_KEY_HI | HPTE_R_KEY_LO);
+	r |= (flags << 55) & HPTE_R_PP0;
+	r |= (flags << 48) & HPTE_R_KEY_HI;
+	r |= flags & (HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_LO);
+	rb = compute_tlbie_rb(v, r, pte_index);
+	hpte[0] = v & ~HPTE_V_VALID;
+	if (!(flags & H_LOCAL)) {
+		while(!try_lock_tlbie(&kvm->arch.tlbie_lock))
+			cpu_relax();
+		asm volatile("ptesync" : : : "memory");
+		asm volatile(PPC_TLBIE(%1,%0)"; eieio; tlbsync"
+			     : : "r" (rb), "r" (kvm->arch.lpid));
+		asm volatile("ptesync" : : : "memory");
+		kvm->arch.tlbie_lock = 0;
+	} else {
+		asm volatile("ptesync" : : : "memory");
+		asm volatile("tlbiel %0" : : "r" (rb));
+		asm volatile("ptesync" : : : "memory");
+	}
+	hpte[1] = r;
+	eieio();
+	hpte[0] = v & ~HPTE_V_HVLOCK;
+	asm volatile("ptesync" : : : "memory");
+	return H_SUCCESS;
+}
+
+static unsigned long reverse_xlate(struct kvm *kvm, unsigned long realaddr)
+{
+	long int i;
+	unsigned long offset, rpn;
+
+	offset = realaddr & (kvm->arch.ram_psize - 1);
+	rpn = (realaddr - offset) >> PAGE_SHIFT;
+	for (i = 0; i < kvm->arch.ram_npages; ++i)
+		if (rpn == kvm->arch.ram_pginfo[i].pfn)
+			return (i << PAGE_SHIFT) + offset;
+	return HPTE_R_RPN;	/* all 1s in the RPN field */
+}
+
+long kvmppc_h_read(struct kvm_vcpu *vcpu, unsigned long flags,
+		   unsigned long pte_index)
+{
+	struct kvm *kvm = vcpu->kvm;
+	unsigned long *hpte, r;
+	int i, n = 1;
+
+	if (pte_index >= (HPT_NPTEG << 3))
+		return H_PARAMETER;
+	if (flags & H_READ_4) {
+		pte_index &= ~3;
+		n = 4;
+	}
+	for (i = 0; i < n; ++i, ++pte_index) {
+		hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
+		r = hpte[1];
+		if ((flags & H_R_XLATE) && (hpte[0] & HPTE_V_VALID))
+			r = reverse_xlate(kvm, r & HPTE_R_RPN) |
+				(r & ~HPTE_R_RPN);
+		vcpu->arch.gpr[4 + i * 2] = hpte[0];
+		vcpu->arch.gpr[5 + i * 2] = r;
+	}
+	return H_SUCCESS;
+}