linux/arch/powerpc/kvm/book3s_64_mmu_host.c
Alexander Graf 89b68c96a2 KVM: PPC: Book3S: Make magic page properly 4k mappable
The magic page is defined as a 4k page of per-vCPU data that is shared
between the guest and the host to accelerate accesses to privileged
registers.

However, when the host is using 64k page size granularity we weren't quite
as strict about that rule anymore. Instead, we partially treated all of the
upper 64k as magic page and mapped only the uppermost 4k with the actual
magic contents.

This works well enough for Linux which doesn't use any memory in kernel
space in the upper 64k, but Mac OS X got upset. So this patch makes magic
page actually stay in a 4k range even on 64k page size hosts.

This patch fixes magic page usage with Mac OS X (using MOL) on 64k PAGE_SIZE
hosts for me.

Signed-off-by: Alexander Graf <agraf@suse.de>
2014-07-28 15:23:11 +02:00

404 lines
10 KiB
C

/*
* 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_pr.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_vpn,
pte->pagesize, pte->pagesize, 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 (kvmppc_get_msr(vcpu) & 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,
bool iswrite)
{
unsigned long vpn;
pfn_t hpaddr;
ulong hash, hpteg;
u64 vsid;
int ret;
int rflags = 0x192;
int vflags = 0;
int attempt = 0;
struct kvmppc_sid_map *map;
int r = 0;
int hpsize = MMU_PAGE_4K;
bool writable;
unsigned long mmu_seq;
struct kvm *kvm = vcpu->kvm;
struct hpte_cache *cpte;
unsigned long gfn = orig_pte->raddr >> PAGE_SHIFT;
unsigned long pfn;
/* used to check for invalidations in progress */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
/* Get host physical address for gpa */
pfn = kvmppc_gpa_to_pfn(vcpu, orig_pte->raddr, iswrite, &writable);
if (is_error_noslot_pfn(pfn)) {
printk(KERN_INFO "Couldn't get guest page for gpa %lx!\n",
orig_pte->raddr);
r = -EINVAL;
goto out;
}
hpaddr = pfn << PAGE_SHIFT;
/* 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);
r = -EINVAL;
goto out;
}
vpn = hpt_vpn(orig_pte->eaddr, map->host_vsid, MMU_SEGSIZE_256M);
kvm_set_pfn_accessed(pfn);
if (!orig_pte->may_write || !writable)
rflags |= PP_RXRX;
else {
mark_page_dirty(vcpu->kvm, gfn);
kvm_set_pfn_dirty(pfn);
}
if (!orig_pte->may_execute)
rflags |= HPTE_R_N;
else
kvmppc_mmu_flush_icache(pfn);
/*
* Use 64K pages if possible; otherwise, on 64K page kernels,
* we need to transfer 4 more bits from guest real to host real addr.
*/
if (vsid & VSID_64K)
hpsize = MMU_PAGE_64K;
else
hpaddr |= orig_pte->raddr & (~0xfffULL & ~PAGE_MASK);
hash = hpt_hash(vpn, mmu_psize_defs[hpsize].shift, MMU_SEGSIZE_256M);
cpte = kvmppc_mmu_hpte_cache_next(vcpu);
spin_lock(&kvm->mmu_lock);
if (!cpte || mmu_notifier_retry(kvm, mmu_seq)) {
r = -EAGAIN;
goto out_unlock;
}
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) {
r = -1;
goto out_unlock;
}
ret = ppc_md.hpte_insert(hpteg, vpn, hpaddr, rflags, vflags,
hpsize, hpsize, 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 {
trace_kvm_book3s_64_mmu_map(rflags, hpteg,
vpn, 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);
}
cpte->slot = hpteg + (ret & 7);
cpte->host_vpn = vpn;
cpte->pte = *orig_pte;
cpte->pfn = pfn;
cpte->pagesize = hpsize;
kvmppc_mmu_hpte_cache_map(vcpu, cpte);
cpte = NULL;
}
out_unlock:
spin_unlock(&kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
if (cpte)
kvmppc_mmu_hpte_cache_free(cpte);
out:
return r;
}
void kvmppc_mmu_unmap_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *pte)
{
u64 mask = 0xfffffffffULL;
u64 vsid;
vcpu->arch.mmu.esid_to_vsid(vcpu, pte->eaddr >> SID_SHIFT, &vsid);
if (vsid & VSID_64K)
mask = 0xffffffff0ULL;
kvmppc_mmu_pte_vflush(vcpu, pte->vpage, mask);
}
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 (kvmppc_get_msr(vcpu) & 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->proto_vsid_next == vcpu_book3s->proto_vsid_max) {
vcpu_book3s->proto_vsid_next = vcpu_book3s->proto_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 = vsid_scramble(vcpu_book3s->proto_vsid_next++, 256M);
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)
{
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
int i;
int max_slb_size = 64;
int found_inval = -1;
int r;
/* Are we overwriting? */
for (i = 0; i < svcpu->slb_max; i++) {
if (!(svcpu->slb[i].esid & SLB_ESID_V))
found_inval = i;
else if ((svcpu->slb[i].esid & ESID_MASK) == esid) {
r = i;
goto out;
}
}
/* Found a spare entry that was invalidated before */
if (found_inval >= 0) {
r = found_inval;
goto out;
}
/* No spare invalid entry, so create one */
if (mmu_slb_size < 64)
max_slb_size = mmu_slb_size;
/* Overflowing -> purge */
if ((svcpu->slb_max) == max_slb_size)
kvmppc_mmu_flush_segments(vcpu);
r = svcpu->slb_max;
svcpu->slb_max++;
out:
svcpu_put(svcpu);
return r;
}
int kvmppc_mmu_map_segment(struct kvm_vcpu *vcpu, ulong eaddr)
{
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
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;
int r = 0;
slb_index = kvmppc_mmu_next_segment(vcpu, eaddr & ESID_MASK);
if (vcpu->arch.mmu.esid_to_vsid(vcpu, esid, &gvsid)) {
/* Invalidate an entry */
svcpu->slb[slb_index].esid = 0;
r = -ENOENT;
goto out;
}
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;
#ifdef CONFIG_PPC_64K_PAGES
/* Set host segment base page size to 64K if possible */
if (gvsid & VSID_64K)
slb_vsid |= mmu_psize_defs[MMU_PAGE_64K].sllp;
#endif
svcpu->slb[slb_index].esid = slb_esid;
svcpu->slb[slb_index].vsid = slb_vsid;
trace_kvm_book3s_slbmte(slb_vsid, slb_esid);
out:
svcpu_put(svcpu);
return r;
}
void kvmppc_mmu_flush_segment(struct kvm_vcpu *vcpu, ulong ea, ulong seg_size)
{
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
ulong seg_mask = -seg_size;
int i;
for (i = 0; i < svcpu->slb_max; i++) {
if ((svcpu->slb[i].esid & SLB_ESID_V) &&
(svcpu->slb[i].esid & seg_mask) == ea) {
/* Invalidate this entry */
svcpu->slb[i].esid = 0;
}
}
svcpu_put(svcpu);
}
void kvmppc_mmu_flush_segments(struct kvm_vcpu *vcpu)
{
struct kvmppc_book3s_shadow_vcpu *svcpu = svcpu_get(vcpu);
svcpu->slb_max = 0;
svcpu->slb[0].esid = 0;
svcpu_put(svcpu);
}
void kvmppc_mmu_destroy_pr(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->proto_vsid_max = ((u64)(vcpu3s->context_id[0] + 1)
<< ESID_BITS) - 1;
vcpu3s->proto_vsid_first = (u64)vcpu3s->context_id[0] << ESID_BITS;
vcpu3s->proto_vsid_next = vcpu3s->proto_vsid_first;
kvmppc_mmu_hpte_init(vcpu);
return 0;
}