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linux-stable/arch/powerpc/kvm/book3s_hv_rm_mmu.c
Paul Mackerras 9d0ef5ea04 KVM: PPC: Allow I/O mappings in memory slots 
This provides for the case where userspace maps an I/O device into the
address range of a memory slot using a VM_PFNMAP mapping.  In that
case, we work out the pfn from vma->vm_pgoff, and record the cache
enable bits from vma->vm_page_prot in two low-order bits in the
slot_phys array entries.  Then, in kvmppc_h_enter() we check that the
cache bits in the HPTE that the guest wants to insert match the cache
bits in the slot_phys array entry.  However, we do allow the guest to
create what it thinks is a non-cacheable or write-through mapping to
memory that is actually cacheable, so that we can use normal system
memory as part of an emulated device later on.  In that case the actual
HPTE we insert is a cacheable HPTE.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:37 +02:00

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/*
* 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 <linux/module.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>
/*
* Since this file is built in even if KVM is a module, we need
* a local copy of this function for the case where kvm_main.c is
* modular.
*/
static struct kvm_memory_slot *builtin_gfn_to_memslot(struct kvm *kvm,
gfn_t gfn)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, slots)
if (gfn >= memslot->base_gfn &&
gfn < memslot->base_gfn + memslot->npages)
return memslot;
return NULL;
}
/* Translate address of a vmalloc'd thing to a linear map address */
static void *real_vmalloc_addr(void *x)
{
unsigned long addr = (unsigned long) x;
pte_t *p;
p = find_linux_pte(swapper_pg_dir, addr);
if (!p || !pte_present(*p))
return NULL;
/* assume we don't have huge pages in vmalloc space... */
addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
return __va(addr);
}
long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel)
{
struct kvm *kvm = vcpu->kvm;
unsigned long i, pa, gpa, gfn, psize;
unsigned long slot_fn;
unsigned long *hpte;
struct revmap_entry *rev;
unsigned long g_ptel = ptel;
struct kvm_memory_slot *memslot;
unsigned long *physp, pte_size;
unsigned long is_io;
bool realmode = vcpu->arch.vcore->vcore_state == VCORE_RUNNING;
psize = hpte_page_size(pteh, ptel);
if (!psize)
return H_PARAMETER;
/* Find the memslot (if any) for this address */
gpa = (ptel & HPTE_R_RPN) & ~(psize - 1);
gfn = gpa >> PAGE_SHIFT;
memslot = builtin_gfn_to_memslot(kvm, gfn);
if (!(memslot && !(memslot->flags & KVM_MEMSLOT_INVALID)))
return H_PARAMETER;
/* Check if the requested page fits entirely in the memslot. */
if (!slot_is_aligned(memslot, psize))
return H_PARAMETER;
slot_fn = gfn - memslot->base_gfn;
physp = kvm->arch.slot_phys[memslot->id];
if (!physp)
return H_PARAMETER;
physp += slot_fn;
if (realmode)
physp = real_vmalloc_addr(physp);
pa = *physp;
if (!pa)
return H_TOO_HARD;
is_io = pa & (HPTE_R_I | HPTE_R_W);
pte_size = PAGE_SIZE << (pa & KVMPPC_PAGE_ORDER_MASK);
pa &= PAGE_MASK;
if (pte_size < psize)
return H_PARAMETER;
if (pa && pte_size > psize)
pa |= gpa & (pte_size - 1);
ptel &= ~(HPTE_R_PP0 - psize);
ptel |= pa;
/* Check WIMG */
if (!hpte_cache_flags_ok(ptel, is_io)) {
if (is_io)
return H_PARAMETER;
/*
* Allow guest to map emulated device memory as
* uncacheable, but actually make it cacheable.
*/
ptel &= ~(HPTE_R_W|HPTE_R_I|HPTE_R_G);
ptel |= HPTE_R_M;
}
pteh &= ~0x60UL;
pteh |= HPTE_V_VALID;
if (pte_index >= HPT_NPTE)
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 < 8; ++i) {
if ((*hpte & HPTE_V_VALID) == 0 &&
try_lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID))
break;
hpte += 2;
}
if (i == 8) {
/*
* Since try_lock_hpte doesn't retry (not even stdcx.
* failures), it could be that there is a free slot
* but we transiently failed to lock it. Try again,
* actually locking each slot and checking it.
*/
hpte -= 16;
for (i = 0; i < 8; ++i) {
while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
cpu_relax();
if ((*hpte & HPTE_V_VALID) == 0)
break;
*hpte &= ~HPTE_V_HVLOCK;
hpte += 2;
}
if (i == 8)
return H_PTEG_FULL;
}
pte_index += i;
} else {
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
if (!try_lock_hpte(hpte, HPTE_V_HVLOCK | HPTE_V_VALID)) {
/* Lock the slot and check again */
while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
cpu_relax();
if (*hpte & HPTE_V_VALID) {
*hpte &= ~HPTE_V_HVLOCK;
return H_PTEG_FULL;
}
}
}
/* Save away the guest's idea of the second HPTE dword */
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
if (rev)
rev->guest_rpte = g_ptel;
hpte[1] = ptel;
eieio();
hpte[0] = pteh;
asm volatile("ptesync" : : : "memory");
vcpu->arch.gpr[4] = pte_index;
return H_SUCCESS;
}
EXPORT_SYMBOL_GPL(kvmppc_h_enter);
#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_NPTE)
return H_PARAMETER;
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
while (!try_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_NPTE) {
/* 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 (!try_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;
struct revmap_entry *rev;
unsigned long v, r, rb, mask, bits;
if (pte_index >= HPT_NPTE)
return H_PARAMETER;
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
while (!try_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];
bits = (flags << 55) & HPTE_R_PP0;
bits |= (flags << 48) & HPTE_R_KEY_HI;
bits |= flags & (HPTE_R_PP | HPTE_R_N | HPTE_R_KEY_LO);
/* Update guest view of 2nd HPTE dword */
mask = HPTE_R_PP0 | HPTE_R_PP | HPTE_R_N |
HPTE_R_KEY_HI | HPTE_R_KEY_LO;
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
if (rev) {
r = (rev->guest_rpte & ~mask) | bits;
rev->guest_rpte = r;
}
r = (hpte[1] & ~mask) | bits;
/* Update HPTE */
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;
}
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;
struct revmap_entry *rev = NULL;
if (pte_index >= HPT_NPTE)
return H_PARAMETER;
if (flags & H_READ_4) {
pte_index &= ~3;
n = 4;
}
if (flags & H_R_XLATE)
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
for (i = 0; i < n; ++i, ++pte_index) {
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
r = hpte[1];
if (hpte[0] & HPTE_V_VALID) {
if (rev)
r = rev[i].guest_rpte;
else
r = hpte[1] | HPTE_R_RPN;
}
vcpu->arch.gpr[4 + i * 2] = hpte[0];
vcpu->arch.gpr[5 + i * 2] = r;
}
return H_SUCCESS;
}
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