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linux/arch/powerpc/kvm/book3s_64_mmu_host.c
Alexander Graf 8b6db3bc96 KVM: PPC: Implement correct SID mapping on Book3s_32 
Up until now we were doing segment mappings wrong on Book3s_32. For Book3s_64
we were using a trick where we know that a single mmu_context gives us 16 bits
of context ids.

The mm system on Book3s_32 instead uses a clever algorithm to distribute VSIDs
across the available range, so a context id really only gives us 16 available
VSIDs.

To keep at least a few guest processes in the SID shadow, let's map a number of
contexts that we can use as VSID pool. This makes the code be actually correct
and shouldn't hurt performance too much.

Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24 10:52:15 +02:00

310 lines
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/*
* Copyright (C) 2009 SUSE Linux Products GmbH. All rights reserved.
*
* Authors:
* Alexander Graf <agraf@suse.de>
* Kevin Wolf <mail@kevin-wolf.de>
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/kvm_host.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/mmu-hash64.h>
#include <asm/machdep.h>
#include <asm/mmu_context.h>
#include <asm/hw_irq.h>
#include "trace.h"
#define PTE_SIZE 12
void kvmppc_mmu_invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
{
ppc_md.hpte_invalidate(pte->slot, pte->host_va,
MMU_PAGE_4K, MMU_SEGSIZE_256M,
false);
}
/* We keep 512 gvsid->hvsid entries, mapping the guest ones to the array using
* a hash, so we don't waste cycles on looping */
static u16 kvmppc_sid_hash(struct kvm_vcpu *vcpu, u64 gvsid)
{
return (u16)(((gvsid >> (SID_MAP_BITS * 7)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 6)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 5)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 4)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 3)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 2)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 1)) & SID_MAP_MASK) ^
((gvsid >> (SID_MAP_BITS * 0)) & SID_MAP_MASK));
}
static struct kvmppc_sid_map *find_sid_vsid(struct kvm_vcpu *vcpu, u64 gvsid)
{
struct kvmppc_sid_map *map;
u16 sid_map_mask;
if (vcpu->arch.shared->msr & MSR_PR)
gvsid |= VSID_PR;
sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
map = &to_book3s(vcpu)->sid_map[sid_map_mask];
if (map->valid && (map->guest_vsid == gvsid)) {
trace_kvm_book3s_slb_found(gvsid, map->host_vsid);
return map;
}
map = &to_book3s(vcpu)->sid_map[SID_MAP_MASK - sid_map_mask];
if (map->valid && (map->guest_vsid == gvsid)) {
trace_kvm_book3s_slb_found(gvsid, map->host_vsid);
return map;
}
trace_kvm_book3s_slb_fail(sid_map_mask, gvsid);
return NULL;
}
int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte)
{
pfn_t hpaddr;
ulong hash, hpteg, va;
u64 vsid;
int ret;
int rflags = 0x192;
int vflags = 0;
int attempt = 0;
struct kvmppc_sid_map *map;
/* Get host physical address for gpa */
hpaddr = kvmppc_gfn_to_pfn(vcpu, orig_pte->raddr >> PAGE_SHIFT);
if (is_error_pfn(hpaddr)) {
printk(KERN_INFO "Couldn't get guest page for gfn %lx!\n", orig_pte->eaddr);
return -EINVAL;
}
hpaddr <<= PAGE_SHIFT;
hpaddr |= orig_pte->raddr & (~0xfffULL & ~PAGE_MASK);
/* and write the mapping ea -> hpa into the pt */
vcpu->arch.mmu.esid_to_vsid(vcpu, orig_pte->eaddr >> SID_SHIFT, &vsid);
map = find_sid_vsid(vcpu, vsid);
if (!map) {
ret = kvmppc_mmu_map_segment(vcpu, orig_pte->eaddr);
WARN_ON(ret < 0);
map = find_sid_vsid(vcpu, vsid);
}
if (!map) {
printk(KERN_ERR "KVM: Segment map for 0x%llx (0x%lx) failed\n",
vsid, orig_pte->eaddr);
WARN_ON(true);
return -EINVAL;
}
vsid = map->host_vsid;
va = hpt_va(orig_pte->eaddr, vsid, MMU_SEGSIZE_256M);
if (!orig_pte->may_write)
rflags |= HPTE_R_PP;
else
mark_page_dirty(vcpu->kvm, orig_pte->raddr >> PAGE_SHIFT);
if (!orig_pte->may_execute)
rflags |= HPTE_R_N;
hash = hpt_hash(va, PTE_SIZE, MMU_SEGSIZE_256M);
map_again:
hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
/* In case we tried normal mapping already, let's nuke old entries */
if (attempt > 1)
if (ppc_md.hpte_remove(hpteg) < 0)
return -1;
ret = ppc_md.hpte_insert(hpteg, va, hpaddr, rflags, vflags, MMU_PAGE_4K, MMU_SEGSIZE_256M);
if (ret < 0) {
/* If we couldn't map a primary PTE, try a secondary */
hash = ~hash;
vflags ^= HPTE_V_SECONDARY;
attempt++;
goto map_again;
} else {
struct hpte_cache *pte = kvmppc_mmu_hpte_cache_next(vcpu);
trace_kvm_book3s_64_mmu_map(rflags, hpteg, va, hpaddr, orig_pte);
/* The ppc_md code may give us a secondary entry even though we
asked for a primary. Fix up. */
if ((ret & _PTEIDX_SECONDARY) && !(vflags & HPTE_V_SECONDARY)) {
hash = ~hash;
hpteg = ((hash & htab_hash_mask) * HPTES_PER_GROUP);
}
pte->slot = hpteg + (ret & 7);
pte->host_va = va;
pte->pte = *orig_pte;
pte->pfn = hpaddr >> PAGE_SHIFT;
kvmppc_mmu_hpte_cache_map(vcpu, pte);
}
return 0;
}
static struct kvmppc_sid_map *create_sid_map(struct kvm_vcpu *vcpu, u64 gvsid)
{
struct kvmppc_sid_map *map;
struct kvmppc_vcpu_book3s *vcpu_book3s = to_book3s(vcpu);
u16 sid_map_mask;
static int backwards_map = 0;
if (vcpu->arch.shared->msr & MSR_PR)
gvsid |= VSID_PR;
/* We might get collisions that trap in preceding order, so let's
map them differently */
sid_map_mask = kvmppc_sid_hash(vcpu, gvsid);
if (backwards_map)
sid_map_mask = SID_MAP_MASK - sid_map_mask;
map = &to_book3s(vcpu)->sid_map[sid_map_mask];
/* Make sure we're taking the other map next time */
backwards_map = !backwards_map;
/* Uh-oh ... out of mappings. Let's flush! */
if (vcpu_book3s->vsid_next == vcpu_book3s->vsid_max) {
vcpu_book3s->vsid_next = vcpu_book3s->vsid_first;
memset(vcpu_book3s->sid_map, 0,
sizeof(struct kvmppc_sid_map) * SID_MAP_NUM);
kvmppc_mmu_pte_flush(vcpu, 0, 0);
kvmppc_mmu_flush_segments(vcpu);
}
map->host_vsid = vcpu_book3s->vsid_next++;
map->guest_vsid = gvsid;
map->valid = true;
trace_kvm_book3s_slb_map(sid_map_mask, gvsid, map->host_vsid);
return map;
}
static int kvmppc_mmu_next_segment(struct kvm_vcpu *vcpu, ulong esid)
{
int i;
int max_slb_size = 64;
int found_inval = -1;
int r;
if (!to_svcpu(vcpu)->slb_max)
to_svcpu(vcpu)->slb_max = 1;
/* Are we overwriting? */
for (i = 1; i < to_svcpu(vcpu)->slb_max; i++) {
if (!(to_svcpu(vcpu)->slb[i].esid & SLB_ESID_V))
found_inval = i;
else if ((to_svcpu(vcpu)->slb[i].esid & ESID_MASK) == esid)
return i;
}
/* Found a spare entry that was invalidated before */
if (found_inval > 0)
return found_inval;
/* No spare invalid entry, so create one */
if (mmu_slb_size < 64)
max_slb_size = mmu_slb_size;
/* Overflowing -> purge */
if ((to_svcpu(vcpu)->slb_max) == max_slb_size)
kvmppc_mmu_flush_segments(vcpu);
r = to_svcpu(vcpu)->slb_max;
to_svcpu(vcpu)->slb_max++;
return r;
}
int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
{
u64 esid = eaddr >> SID_SHIFT;
u64 slb_esid = (eaddr & ESID_MASK) | SLB_ESID_V;
u64 slb_vsid = SLB_VSID_USER;
u64 gvsid;
int slb_index;
struct kvmppc_sid_map *map;
slb_index = kvmppc_mmu_next_segment(vcpu, eaddr & ESID_MASK);
if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
/* Invalidate an entry */
to_svcpu(vcpu)->slb[slb_index].esid = 0;
return -ENOENT;
}
map = find_sid_vsid(vcpu, gvsid);
if (!map)
map = create_sid_map(vcpu, gvsid);
map->guest_esid = esid;
slb_vsid |= (map->host_vsid << 12);
slb_vsid &= ~SLB_VSID_KP;
slb_esid |= slb_index;
to_svcpu(vcpu)->slb[slb_index].esid = slb_esid;
to_svcpu(vcpu)->slb[slb_index].vsid = slb_vsid;
trace_kvm_book3s_slbmte(slb_vsid, slb_esid);
return 0;
}
void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
{
to_svcpu(vcpu)->slb_max = 1;
to_svcpu(vcpu)->slb[0].esid = 0;
}
void kvmppc_mmu_destroy(struct kvm_vcpu *vcpu)
{
kvmppc_mmu_hpte_destroy(vcpu);
__destroy_context(to_book3s(vcpu)->context_id[0]);
}
int kvmppc_mmu_init(struct kvm_vcpu *vcpu)
{
struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
int err;
err = __init_new_context();
if (err < 0)
return -1;
vcpu3s->context_id[0] = err;
vcpu3s->vsid_max = ((vcpu3s->context_id[0] + 1) << USER_ESID_BITS) - 1;
vcpu3s->vsid_first = vcpu3s->context_id[0] << USER_ESID_BITS;
vcpu3s->vsid_next = vcpu3s->vsid_first;
kvmppc_mmu_hpte_init(vcpu);
return 0;
}
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