linux_dsm_epyc7002/arch/powerpc/kvm/book3s_hv_rm_mmu.c
Paul Mackerras 1cc8ed0b13 KVM: PPC: Book3S HV: Don't give the guest RW access to RO pages
Currently, if the guest does an H_PROTECT hcall requesting that the
permissions on a HPT entry be changed to allow writing, we make the
requested change even if the page is marked read-only in the host
Linux page tables.  This is a problem since it would for instance
allow a guest to modify a page that KSM has decided can be shared
between multiple guests.

To fix this, if the new permissions for the page allow writing, we need
to look up the memslot for the page, work out the host virtual address,
and look up the Linux page tables to get the PTE for the page.  If that
PTE is read-only, we reduce the HPTE permissions to read-only.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2012-12-06 01:34:00 +01:00

875 lines
24 KiB
C

/*
* 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>
/* 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);
}
/*
* Add this HPTE into the chain for the real page.
* Must be called with the chain locked; it unlocks the chain.
*/
void kvmppc_add_revmap_chain(struct kvm *kvm, struct revmap_entry *rev,
unsigned long *rmap, long pte_index, int realmode)
{
struct revmap_entry *head, *tail;
unsigned long i;
if (*rmap & KVMPPC_RMAP_PRESENT) {
i = *rmap & KVMPPC_RMAP_INDEX;
head = &kvm->arch.revmap[i];
if (realmode)
head = real_vmalloc_addr(head);
tail = &kvm->arch.revmap[head->back];
if (realmode)
tail = real_vmalloc_addr(tail);
rev->forw = i;
rev->back = head->back;
tail->forw = pte_index;
head->back = pte_index;
} else {
rev->forw = rev->back = pte_index;
*rmap = (*rmap & ~KVMPPC_RMAP_INDEX) |
pte_index | KVMPPC_RMAP_PRESENT;
}
unlock_rmap(rmap);
}
EXPORT_SYMBOL_GPL(kvmppc_add_revmap_chain);
/*
* Note modification of an HPTE; set the HPTE modified bit
* if anyone is interested.
*/
static inline void note_hpte_modification(struct kvm *kvm,
struct revmap_entry *rev)
{
if (atomic_read(&kvm->arch.hpte_mod_interest))
rev->guest_rpte |= HPTE_GR_MODIFIED;
}
/* Remove this HPTE from the chain for a real page */
static void remove_revmap_chain(struct kvm *kvm, long pte_index,
struct revmap_entry *rev,
unsigned long hpte_v, unsigned long hpte_r)
{
struct revmap_entry *next, *prev;
unsigned long gfn, ptel, head;
struct kvm_memory_slot *memslot;
unsigned long *rmap;
unsigned long rcbits;
rcbits = hpte_r & (HPTE_R_R | HPTE_R_C);
ptel = rev->guest_rpte |= rcbits;
gfn = hpte_rpn(ptel, hpte_page_size(hpte_v, ptel));
memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
if (!memslot)
return;
rmap = real_vmalloc_addr(&memslot->arch.rmap[gfn - memslot->base_gfn]);
lock_rmap(rmap);
head = *rmap & KVMPPC_RMAP_INDEX;
next = real_vmalloc_addr(&kvm->arch.revmap[rev->forw]);
prev = real_vmalloc_addr(&kvm->arch.revmap[rev->back]);
next->back = rev->back;
prev->forw = rev->forw;
if (head == pte_index) {
head = rev->forw;
if (head == pte_index)
*rmap &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
else
*rmap = (*rmap & ~KVMPPC_RMAP_INDEX) | head;
}
*rmap |= rcbits << KVMPPC_RMAP_RC_SHIFT;
unlock_rmap(rmap);
}
static pte_t lookup_linux_pte(pgd_t *pgdir, unsigned long hva,
int writing, unsigned long *pte_sizep)
{
pte_t *ptep;
unsigned long ps = *pte_sizep;
unsigned int shift;
ptep = find_linux_pte_or_hugepte(pgdir, hva, &shift);
if (!ptep)
return __pte(0);
if (shift)
*pte_sizep = 1ul << shift;
else
*pte_sizep = PAGE_SIZE;
if (ps > *pte_sizep)
return __pte(0);
if (!pte_present(*ptep))
return __pte(0);
return kvmppc_read_update_linux_pte(ptep, writing);
}
static inline void unlock_hpte(unsigned long *hpte, unsigned long hpte_v)
{
asm volatile(PPC_RELEASE_BARRIER "" : : : "memory");
hpte[0] = hpte_v;
}
long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel,
pgd_t *pgdir, bool realmode, unsigned long *pte_idx_ret)
{
unsigned long i, pa, gpa, gfn, psize;
unsigned long slot_fn, hva;
unsigned long *hpte;
struct revmap_entry *rev;
unsigned long g_ptel;
struct kvm_memory_slot *memslot;
unsigned long *physp, pte_size;
unsigned long is_io;
unsigned long *rmap;
pte_t pte;
unsigned int writing;
unsigned long mmu_seq;
unsigned long rcbits;
psize = hpte_page_size(pteh, ptel);
if (!psize)
return H_PARAMETER;
writing = hpte_is_writable(ptel);
pteh &= ~(HPTE_V_HVLOCK | HPTE_V_ABSENT | HPTE_V_VALID);
ptel &= ~HPTE_GR_RESERVED;
g_ptel = ptel;
/* used later to detect if we might have been invalidated */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
/* Find the memslot (if any) for this address */
gpa = (ptel & HPTE_R_RPN) & ~(psize - 1);
gfn = gpa >> PAGE_SHIFT;
memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
pa = 0;
is_io = ~0ul;
rmap = NULL;
if (!(memslot && !(memslot->flags & KVM_MEMSLOT_INVALID))) {
/* PPC970 can't do emulated MMIO */
if (!cpu_has_feature(CPU_FTR_ARCH_206))
return H_PARAMETER;
/* Emulated MMIO - mark this with key=31 */
pteh |= HPTE_V_ABSENT;
ptel |= HPTE_R_KEY_HI | HPTE_R_KEY_LO;
goto do_insert;
}
/* 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;
rmap = &memslot->arch.rmap[slot_fn];
if (!kvm->arch.using_mmu_notifiers) {
physp = memslot->arch.slot_phys;
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;
} else {
/* Translate to host virtual address */
hva = __gfn_to_hva_memslot(memslot, gfn);
/* Look up the Linux PTE for the backing page */
pte_size = psize;
pte = lookup_linux_pte(pgdir, hva, writing, &pte_size);
if (pte_present(pte)) {
if (writing && !pte_write(pte))
/* make the actual HPTE be read-only */
ptel = hpte_make_readonly(ptel);
is_io = hpte_cache_bits(pte_val(pte));
pa = pte_pfn(pte) << PAGE_SHIFT;
}
}
if (pte_size < psize)
return H_PARAMETER;
if (pa && pte_size > psize)
pa |= gpa & (pte_size - 1);
ptel &= ~(HPTE_R_PP0 - psize);
ptel |= pa;
if (pa)
pteh |= HPTE_V_VALID;
else
pteh |= HPTE_V_ABSENT;
/* Check WIMG */
if (is_io != ~0ul && !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;
}
/* Find and lock the HPTEG slot to use */
do_insert:
if (pte_index >= kvm->arch.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 |
HPTE_V_ABSENT))
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 | HPTE_V_ABSENT)))
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 |
HPTE_V_ABSENT)) {
/* Lock the slot and check again */
while (!try_lock_hpte(hpte, HPTE_V_HVLOCK))
cpu_relax();
if (*hpte & (HPTE_V_VALID | HPTE_V_ABSENT)) {
*hpte &= ~HPTE_V_HVLOCK;
return H_PTEG_FULL;
}
}
}
/* Save away the guest's idea of the second HPTE dword */
rev = &kvm->arch.revmap[pte_index];
if (realmode)
rev = real_vmalloc_addr(rev);
if (rev) {
rev->guest_rpte = g_ptel;
note_hpte_modification(kvm, rev);
}
/* Link HPTE into reverse-map chain */
if (pteh & HPTE_V_VALID) {
if (realmode)
rmap = real_vmalloc_addr(rmap);
lock_rmap(rmap);
/* Check for pending invalidations under the rmap chain lock */
if (kvm->arch.using_mmu_notifiers &&
mmu_notifier_retry(kvm, mmu_seq)) {
/* inval in progress, write a non-present HPTE */
pteh |= HPTE_V_ABSENT;
pteh &= ~HPTE_V_VALID;
unlock_rmap(rmap);
} else {
kvmppc_add_revmap_chain(kvm, rev, rmap, pte_index,
realmode);
/* Only set R/C in real HPTE if already set in *rmap */
rcbits = *rmap >> KVMPPC_RMAP_RC_SHIFT;
ptel &= rcbits | ~(HPTE_R_R | HPTE_R_C);
}
}
hpte[1] = ptel;
/* Write the first HPTE dword, unlocking the HPTE and making it valid */
eieio();
hpte[0] = pteh;
asm volatile("ptesync" : : : "memory");
*pte_idx_ret = pte_index;
return H_SUCCESS;
}
EXPORT_SYMBOL_GPL(kvmppc_do_h_enter);
long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel)
{
return kvmppc_do_h_enter(vcpu->kvm, flags, pte_index, pteh, ptel,
vcpu->arch.pgdir, true, &vcpu->arch.gpr[4]);
}
#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_do_h_remove(struct kvm *kvm, unsigned long flags,
unsigned long pte_index, unsigned long avpn,
unsigned long *hpret)
{
unsigned long *hpte;
unsigned long v, r, rb;
struct revmap_entry *rev;
if (pte_index >= kvm->arch.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_ABSENT | 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;
}
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
v = hpte[0] & ~HPTE_V_HVLOCK;
if (v & HPTE_V_VALID) {
hpte[0] &= ~HPTE_V_VALID;
rb = compute_tlbie_rb(v, hpte[1], pte_index);
if (!(flags & H_LOCAL) && atomic_read(&kvm->online_vcpus) > 1) {
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");
}
/* Read PTE low word after tlbie to get final R/C values */
remove_revmap_chain(kvm, pte_index, rev, v, hpte[1]);
}
r = rev->guest_rpte & ~HPTE_GR_RESERVED;
note_hpte_modification(kvm, rev);
unlock_hpte(hpte, 0);
hpret[0] = v;
hpret[1] = r;
return H_SUCCESS;
}
EXPORT_SYMBOL_GPL(kvmppc_do_h_remove);
long kvmppc_h_remove(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long pte_index, unsigned long avpn)
{
return kvmppc_do_h_remove(vcpu->kvm, flags, pte_index, avpn,
&vcpu->arch.gpr[4]);
}
long kvmppc_h_bulk_remove(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
unsigned long *args = &vcpu->arch.gpr[4];
unsigned long *hp, *hptes[4], tlbrb[4];
long int i, j, k, n, found, indexes[4];
unsigned long flags, req, pte_index, rcbits;
long int local = 0;
long int ret = H_SUCCESS;
struct revmap_entry *rev, *revs[4];
if (atomic_read(&kvm->online_vcpus) == 1)
local = 1;
for (i = 0; i < 4 && ret == H_SUCCESS; ) {
n = 0;
for (; i < 4; ++i) {
j = i * 2;
pte_index = args[j];
flags = pte_index >> 56;
pte_index &= ((1ul << 56) - 1);
req = flags >> 6;
flags &= 3;
if (req == 3) { /* no more requests */
i = 4;
break;
}
if (req != 1 || flags == 3 ||
pte_index >= kvm->arch.hpt_npte) {
/* parameter error */
args[j] = ((0xa0 | flags) << 56) + pte_index;
ret = H_PARAMETER;
break;
}
hp = (unsigned long *)
(kvm->arch.hpt_virt + (pte_index << 4));
/* to avoid deadlock, don't spin except for first */
if (!try_lock_hpte(hp, HPTE_V_HVLOCK)) {
if (n)
break;
while (!try_lock_hpte(hp, HPTE_V_HVLOCK))
cpu_relax();
}
found = 0;
if (hp[0] & (HPTE_V_ABSENT | HPTE_V_VALID)) {
switch (flags & 3) {
case 0: /* absolute */
found = 1;
break;
case 1: /* andcond */
if (!(hp[0] & args[j + 1]))
found = 1;
break;
case 2: /* AVPN */
if ((hp[0] & ~0x7fUL) == args[j + 1])
found = 1;
break;
}
}
if (!found) {
hp[0] &= ~HPTE_V_HVLOCK;
args[j] = ((0x90 | flags) << 56) + pte_index;
continue;
}
args[j] = ((0x80 | flags) << 56) + pte_index;
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
note_hpte_modification(kvm, rev);
if (!(hp[0] & HPTE_V_VALID)) {
/* insert R and C bits from PTE */
rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
args[j] |= rcbits << (56 - 5);
hp[0] = 0;
continue;
}
hp[0] &= ~HPTE_V_VALID; /* leave it locked */
tlbrb[n] = compute_tlbie_rb(hp[0], hp[1], pte_index);
indexes[n] = j;
hptes[n] = hp;
revs[n] = rev;
++n;
}
if (!n)
break;
/* Now that we've collected a batch, do the tlbies */
if (!local) {
while(!try_lock_tlbie(&kvm->arch.tlbie_lock))
cpu_relax();
asm volatile("ptesync" : : : "memory");
for (k = 0; k < n; ++k)
asm volatile(PPC_TLBIE(%1,%0) : :
"r" (tlbrb[k]),
"r" (kvm->arch.lpid));
asm volatile("eieio; tlbsync; ptesync" : : : "memory");
kvm->arch.tlbie_lock = 0;
} else {
asm volatile("ptesync" : : : "memory");
for (k = 0; k < n; ++k)
asm volatile("tlbiel %0" : : "r" (tlbrb[k]));
asm volatile("ptesync" : : : "memory");
}
/* Read PTE low words after tlbie to get final R/C values */
for (k = 0; k < n; ++k) {
j = indexes[k];
pte_index = args[j] & ((1ul << 56) - 1);
hp = hptes[k];
rev = revs[k];
remove_revmap_chain(kvm, pte_index, rev, hp[0], hp[1]);
rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
args[j] |= rcbits << (56 - 5);
hp[0] = 0;
}
}
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 >= kvm->arch.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_ABSENT | 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;
note_hpte_modification(kvm, rev);
}
r = (hpte[1] & ~mask) | bits;
/* Update HPTE */
if (v & HPTE_V_VALID) {
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");
}
/*
* If the host has this page as readonly but the guest
* wants to make it read/write, reduce the permissions.
* Checking the host permissions involves finding the
* memslot and then the Linux PTE for the page.
*/
if (hpte_is_writable(r) && kvm->arch.using_mmu_notifiers) {
unsigned long psize, gfn, hva;
struct kvm_memory_slot *memslot;
pgd_t *pgdir = vcpu->arch.pgdir;
pte_t pte;
psize = hpte_page_size(v, r);
gfn = ((r & HPTE_R_RPN) & ~(psize - 1)) >> PAGE_SHIFT;
memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn);
if (memslot) {
hva = __gfn_to_hva_memslot(memslot, gfn);
pte = lookup_linux_pte(pgdir, hva, 1, &psize);
if (pte_present(pte) && !pte_write(pte))
r = hpte_make_readonly(r);
}
}
}
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, v, r;
int i, n = 1;
struct revmap_entry *rev = NULL;
if (pte_index >= kvm->arch.hpt_npte)
return H_PARAMETER;
if (flags & H_READ_4) {
pte_index &= ~3;
n = 4;
}
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));
v = hpte[0] & ~HPTE_V_HVLOCK;
r = hpte[1];
if (v & HPTE_V_ABSENT) {
v &= ~HPTE_V_ABSENT;
v |= HPTE_V_VALID;
}
if (v & HPTE_V_VALID) {
r = rev[i].guest_rpte | (r & (HPTE_R_R | HPTE_R_C));
r &= ~HPTE_GR_RESERVED;
}
vcpu->arch.gpr[4 + i * 2] = v;
vcpu->arch.gpr[5 + i * 2] = r;
}
return H_SUCCESS;
}
void kvmppc_invalidate_hpte(struct kvm *kvm, unsigned long *hptep,
unsigned long pte_index)
{
unsigned long rb;
hptep[0] &= ~HPTE_V_VALID;
rb = compute_tlbie_rb(hptep[0], hptep[1], pte_index);
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;
}
EXPORT_SYMBOL_GPL(kvmppc_invalidate_hpte);
void kvmppc_clear_ref_hpte(struct kvm *kvm, unsigned long *hptep,
unsigned long pte_index)
{
unsigned long rb;
unsigned char rbyte;
rb = compute_tlbie_rb(hptep[0], hptep[1], pte_index);
rbyte = (hptep[1] & ~HPTE_R_R) >> 8;
/* modify only the second-last byte, which contains the ref bit */
*((char *)hptep + 14) = rbyte;
while (!try_lock_tlbie(&kvm->arch.tlbie_lock))
cpu_relax();
asm volatile(PPC_TLBIE(%1,%0)"; eieio; tlbsync"
: : "r" (rb), "r" (kvm->arch.lpid));
asm volatile("ptesync" : : : "memory");
kvm->arch.tlbie_lock = 0;
}
EXPORT_SYMBOL_GPL(kvmppc_clear_ref_hpte);
static int slb_base_page_shift[4] = {
24, /* 16M */
16, /* 64k */
34, /* 16G */
20, /* 1M, unsupported */
};
long kvmppc_hv_find_lock_hpte(struct kvm *kvm, gva_t eaddr, unsigned long slb_v,
unsigned long valid)
{
unsigned int i;
unsigned int pshift;
unsigned long somask;
unsigned long vsid, hash;
unsigned long avpn;
unsigned long *hpte;
unsigned long mask, val;
unsigned long v, r;
/* Get page shift, work out hash and AVPN etc. */
mask = SLB_VSID_B | HPTE_V_AVPN | HPTE_V_SECONDARY;
val = 0;
pshift = 12;
if (slb_v & SLB_VSID_L) {
mask |= HPTE_V_LARGE;
val |= HPTE_V_LARGE;
pshift = slb_base_page_shift[(slb_v & SLB_VSID_LP) >> 4];
}
if (slb_v & SLB_VSID_B_1T) {
somask = (1UL << 40) - 1;
vsid = (slb_v & ~SLB_VSID_B) >> SLB_VSID_SHIFT_1T;
vsid ^= vsid << 25;
} else {
somask = (1UL << 28) - 1;
vsid = (slb_v & ~SLB_VSID_B) >> SLB_VSID_SHIFT;
}
hash = (vsid ^ ((eaddr & somask) >> pshift)) & kvm->arch.hpt_mask;
avpn = slb_v & ~(somask >> 16); /* also includes B */
avpn |= (eaddr & somask) >> 16;
if (pshift >= 24)
avpn &= ~((1UL << (pshift - 16)) - 1);
else
avpn &= ~0x7fUL;
val |= avpn;
for (;;) {
hpte = (unsigned long *)(kvm->arch.hpt_virt + (hash << 7));
for (i = 0; i < 16; i += 2) {
/* Read the PTE racily */
v = hpte[i] & ~HPTE_V_HVLOCK;
/* Check valid/absent, hash, segment size and AVPN */
if (!(v & valid) || (v & mask) != val)
continue;
/* Lock the PTE and read it under the lock */
while (!try_lock_hpte(&hpte[i], HPTE_V_HVLOCK))
cpu_relax();
v = hpte[i] & ~HPTE_V_HVLOCK;
r = hpte[i+1];
/*
* Check the HPTE again, including large page size
* Since we don't currently allow any MPSS (mixed
* page-size segment) page sizes, it is sufficient
* to check against the actual page size.
*/
if ((v & valid) && (v & mask) == val &&
hpte_page_size(v, r) == (1ul << pshift))
/* Return with the HPTE still locked */
return (hash << 3) + (i >> 1);
/* Unlock and move on */
hpte[i] = v;
}
if (val & HPTE_V_SECONDARY)
break;
val |= HPTE_V_SECONDARY;
hash = hash ^ kvm->arch.hpt_mask;
}
return -1;
}
EXPORT_SYMBOL(kvmppc_hv_find_lock_hpte);
/*
* Called in real mode to check whether an HPTE not found fault
* is due to accessing a paged-out page or an emulated MMIO page,
* or if a protection fault is due to accessing a page that the
* guest wanted read/write access to but which we made read-only.
* Returns a possibly modified status (DSISR) value if not
* (i.e. pass the interrupt to the guest),
* -1 to pass the fault up to host kernel mode code, -2 to do that
* and also load the instruction word (for MMIO emulation),
* or 0 if we should make the guest retry the access.
*/
long kvmppc_hpte_hv_fault(struct kvm_vcpu *vcpu, unsigned long addr,
unsigned long slb_v, unsigned int status, bool data)
{
struct kvm *kvm = vcpu->kvm;
long int index;
unsigned long v, r, gr;
unsigned long *hpte;
unsigned long valid;
struct revmap_entry *rev;
unsigned long pp, key;
/* For protection fault, expect to find a valid HPTE */
valid = HPTE_V_VALID;
if (status & DSISR_NOHPTE)
valid |= HPTE_V_ABSENT;
index = kvmppc_hv_find_lock_hpte(kvm, addr, slb_v, valid);
if (index < 0) {
if (status & DSISR_NOHPTE)
return status; /* there really was no HPTE */
return 0; /* for prot fault, HPTE disappeared */
}
hpte = (unsigned long *)(kvm->arch.hpt_virt + (index << 4));
v = hpte[0] & ~HPTE_V_HVLOCK;
r = hpte[1];
rev = real_vmalloc_addr(&kvm->arch.revmap[index]);
gr = rev->guest_rpte;
unlock_hpte(hpte, v);
/* For not found, if the HPTE is valid by now, retry the instruction */
if ((status & DSISR_NOHPTE) && (v & HPTE_V_VALID))
return 0;
/* Check access permissions to the page */
pp = gr & (HPTE_R_PP0 | HPTE_R_PP);
key = (vcpu->arch.shregs.msr & MSR_PR) ? SLB_VSID_KP : SLB_VSID_KS;
status &= ~DSISR_NOHPTE; /* DSISR_NOHPTE == SRR1_ISI_NOPT */
if (!data) {
if (gr & (HPTE_R_N | HPTE_R_G))
return status | SRR1_ISI_N_OR_G;
if (!hpte_read_permission(pp, slb_v & key))
return status | SRR1_ISI_PROT;
} else if (status & DSISR_ISSTORE) {
/* check write permission */
if (!hpte_write_permission(pp, slb_v & key))
return status | DSISR_PROTFAULT;
} else {
if (!hpte_read_permission(pp, slb_v & key))
return status | DSISR_PROTFAULT;
}
/* Check storage key, if applicable */
if (data && (vcpu->arch.shregs.msr & MSR_DR)) {
unsigned int perm = hpte_get_skey_perm(gr, vcpu->arch.amr);
if (status & DSISR_ISSTORE)
perm >>= 1;
if (perm & 1)
return status | DSISR_KEYFAULT;
}
/* Save HPTE info for virtual-mode handler */
vcpu->arch.pgfault_addr = addr;
vcpu->arch.pgfault_index = index;
vcpu->arch.pgfault_hpte[0] = v;
vcpu->arch.pgfault_hpte[1] = r;
/* Check the storage key to see if it is possibly emulated MMIO */
if (data && (vcpu->arch.shregs.msr & MSR_IR) &&
(r & (HPTE_R_KEY_HI | HPTE_R_KEY_LO)) ==
(HPTE_R_KEY_HI | HPTE_R_KEY_LO))
return -2; /* MMIO emulation - load instr word */
return -1; /* send fault up to host kernel mode */
}