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linux-sg2042/arch/powerpc/kvm/book3s_64_mmu_radix.c

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34 KiB
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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 2016 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/anon_inodes.h>
#include <linux/file.h>
#include <linux/debugfs.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/pte-walk.h>
/*
* Supported radix tree geometry.
* Like p9, we support either 5 or 9 bits at the first (lowest) level,
* for a page size of 64k or 4k.
*/
static int p9_supported_radix_bits[4] = { 5, 9, 9, 13 };
unsigned long __kvmhv_copy_tofrom_guest_radix(int lpid, int pid,
gva_t eaddr, void *to, void *from,
unsigned long n)
{
int uninitialized_var(old_pid), old_lpid;
unsigned long quadrant, ret = n;
bool is_load = !!to;
/* Can't access quadrants 1 or 2 in non-HV mode, call the HV to do it */
if (kvmhv_on_pseries())
return plpar_hcall_norets(H_COPY_TOFROM_GUEST, lpid, pid, eaddr,
__pa(to), __pa(from), n);
quadrant = 1;
if (!pid)
quadrant = 2;
if (is_load)
from = (void *) (eaddr | (quadrant << 62));
else
to = (void *) (eaddr | (quadrant << 62));
preempt_disable();
/* switch the lpid first to avoid running host with unallocated pid */
old_lpid = mfspr(SPRN_LPID);
if (old_lpid != lpid)
mtspr(SPRN_LPID, lpid);
if (quadrant == 1) {
old_pid = mfspr(SPRN_PID);
if (old_pid != pid)
mtspr(SPRN_PID, pid);
}
isync();
pagefault_disable();
if (is_load)
ret = raw_copy_from_user(to, from, n);
else
ret = raw_copy_to_user(to, from, n);
pagefault_enable();
/* switch the pid first to avoid running host with unallocated pid */
if (quadrant == 1 && pid != old_pid)
mtspr(SPRN_PID, old_pid);
if (lpid != old_lpid)
mtspr(SPRN_LPID, old_lpid);
isync();
preempt_enable();
return ret;
}
EXPORT_SYMBOL_GPL(__kvmhv_copy_tofrom_guest_radix);
static long kvmhv_copy_tofrom_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr,
void *to, void *from, unsigned long n)
{
int lpid = vcpu->kvm->arch.lpid;
int pid = vcpu->arch.pid;
/* This would cause a data segment intr so don't allow the access */
if (eaddr & (0x3FFUL << 52))
return -EINVAL;
/* Should we be using the nested lpid */
if (vcpu->arch.nested)
lpid = vcpu->arch.nested->shadow_lpid;
/* If accessing quadrant 3 then pid is expected to be 0 */
if (((eaddr >> 62) & 0x3) == 0x3)
pid = 0;
eaddr &= ~(0xFFFUL << 52);
return __kvmhv_copy_tofrom_guest_radix(lpid, pid, eaddr, to, from, n);
}
long kvmhv_copy_from_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr, void *to,
unsigned long n)
{
long ret;
ret = kvmhv_copy_tofrom_guest_radix(vcpu, eaddr, to, NULL, n);
if (ret > 0)
memset(to + (n - ret), 0, ret);
return ret;
}
EXPORT_SYMBOL_GPL(kvmhv_copy_from_guest_radix);
long kvmhv_copy_to_guest_radix(struct kvm_vcpu *vcpu, gva_t eaddr, void *from,
unsigned long n)
{
return kvmhv_copy_tofrom_guest_radix(vcpu, eaddr, NULL, from, n);
}
EXPORT_SYMBOL_GPL(kvmhv_copy_to_guest_radix);
int kvmppc_mmu_walk_radix_tree(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, u64 root,
u64 *pte_ret_p)
{
struct kvm *kvm = vcpu->kvm;
int ret, level, ps;
unsigned long rts, bits, offset, index;
u64 pte, base, gpa;
__be64 rpte;
rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
((root & RTS2_MASK) >> RTS2_SHIFT);
bits = root & RPDS_MASK;
base = root & RPDB_MASK;
offset = rts + 31;
/* Current implementations only support 52-bit space */
if (offset != 52)
return -EINVAL;
/* Walk each level of the radix tree */
for (level = 3; level >= 0; --level) {
u64 addr;
/* Check a valid size */
if (level && bits != p9_supported_radix_bits[level])
return -EINVAL;
if (level == 0 && !(bits == 5 || bits == 9))
return -EINVAL;
offset -= bits;
index = (eaddr >> offset) & ((1UL << bits) - 1);
/* Check that low bits of page table base are zero */
if (base & ((1UL << (bits + 3)) - 1))
return -EINVAL;
/* Read the entry from guest memory */
addr = base + (index * sizeof(rpte));
ret = kvm_read_guest(kvm, addr, &rpte, sizeof(rpte));
if (ret) {
if (pte_ret_p)
*pte_ret_p = addr;
return ret;
}
pte = __be64_to_cpu(rpte);
if (!(pte & _PAGE_PRESENT))
return -ENOENT;
/* Check if a leaf entry */
if (pte & _PAGE_PTE)
break;
/* Get ready to walk the next level */
base = pte & RPDB_MASK;
bits = pte & RPDS_MASK;
}
/* Need a leaf at lowest level; 512GB pages not supported */
if (level < 0 || level == 3)
return -EINVAL;
/* We found a valid leaf PTE */
/* Offset is now log base 2 of the page size */
gpa = pte & 0x01fffffffffff000ul;
if (gpa & ((1ul << offset) - 1))
return -EINVAL;
gpa |= eaddr & ((1ul << offset) - 1);
for (ps = MMU_PAGE_4K; ps < MMU_PAGE_COUNT; ++ps)
if (offset == mmu_psize_defs[ps].shift)
break;
gpte->page_size = ps;
gpte->page_shift = offset;
gpte->eaddr = eaddr;
gpte->raddr = gpa;
/* Work out permissions */
gpte->may_read = !!(pte & _PAGE_READ);
gpte->may_write = !!(pte & _PAGE_WRITE);
gpte->may_execute = !!(pte & _PAGE_EXEC);
gpte->rc = pte & (_PAGE_ACCESSED | _PAGE_DIRTY);
if (pte_ret_p)
*pte_ret_p = pte;
return 0;
}
/*
* Used to walk a partition or process table radix tree in guest memory
* Note: We exploit the fact that a partition table and a process
* table have the same layout, a partition-scoped page table and a
* process-scoped page table have the same layout, and the 2nd
* doubleword of a partition table entry has the same layout as
* the PTCR register.
*/
int kvmppc_mmu_radix_translate_table(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, u64 table,
int table_index, u64 *pte_ret_p)
{
struct kvm *kvm = vcpu->kvm;
int ret;
unsigned long size, ptbl, root;
struct prtb_entry entry;
if ((table & PRTS_MASK) > 24)
return -EINVAL;
size = 1ul << ((table & PRTS_MASK) + 12);
/* Is the table big enough to contain this entry? */
if ((table_index * sizeof(entry)) >= size)
return -EINVAL;
/* Read the table to find the root of the radix tree */
ptbl = (table & PRTB_MASK) + (table_index * sizeof(entry));
ret = kvm_read_guest(kvm, ptbl, &entry, sizeof(entry));
if (ret)
return ret;
/* Root is stored in the first double word */
root = be64_to_cpu(entry.prtb0);
return kvmppc_mmu_walk_radix_tree(vcpu, eaddr, gpte, root, pte_ret_p);
}
int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, bool data, bool iswrite)
{
u32 pid;
u64 pte;
int ret;
/* Work out effective PID */
switch (eaddr >> 62) {
case 0:
pid = vcpu->arch.pid;
break;
case 3:
pid = 0;
break;
default:
return -EINVAL;
}
ret = kvmppc_mmu_radix_translate_table(vcpu, eaddr, gpte,
vcpu->kvm->arch.process_table, pid, &pte);
if (ret)
return ret;
/* Check privilege (applies only to process scoped translations) */
if (kvmppc_get_msr(vcpu) & MSR_PR) {
if (pte & _PAGE_PRIVILEGED) {
gpte->may_read = 0;
gpte->may_write = 0;
gpte->may_execute = 0;
}
} else {
if (!(pte & _PAGE_PRIVILEGED)) {
/* Check AMR/IAMR to see if strict mode is in force */
if (vcpu->arch.amr & (1ul << 62))
gpte->may_read = 0;
if (vcpu->arch.amr & (1ul << 63))
gpte->may_write = 0;
if (vcpu->arch.iamr & (1ul << 62))
gpte->may_execute = 0;
}
}
return 0;
}
void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
unsigned int pshift, unsigned int lpid)
{
unsigned long psize = PAGE_SIZE;
int psi;
long rc;
unsigned long rb;
if (pshift)
psize = 1UL << pshift;
else
pshift = PAGE_SHIFT;
addr &= ~(psize - 1);
if (!kvmhv_on_pseries()) {
radix__flush_tlb_lpid_page(lpid, addr, psize);
return;
}
psi = shift_to_mmu_psize(pshift);
rb = addr | (mmu_get_ap(psi) << PPC_BITLSHIFT(58));
rc = plpar_hcall_norets(H_TLB_INVALIDATE, H_TLBIE_P1_ENC(0, 0, 1),
lpid, rb);
if (rc)
pr_err("KVM: TLB page invalidation hcall failed, rc=%ld\n", rc);
}
static void kvmppc_radix_flush_pwc(struct kvm *kvm, unsigned int lpid)
{
long rc;
if (!kvmhv_on_pseries()) {
radix__flush_pwc_lpid(lpid);
return;
}
rc = plpar_hcall_norets(H_TLB_INVALIDATE, H_TLBIE_P1_ENC(1, 0, 1),
lpid, TLBIEL_INVAL_SET_LPID);
if (rc)
pr_err("KVM: TLB PWC invalidation hcall failed, rc=%ld\n", rc);
}
static unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
unsigned long clr, unsigned long set,
unsigned long addr, unsigned int shift)
{
return __radix_pte_update(ptep, clr, set);
}
void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
radix__set_pte_at(kvm->mm, addr, ptep, pte, 0);
}
static struct kmem_cache *kvm_pte_cache;
static struct kmem_cache *kvm_pmd_cache;
static pte_t *kvmppc_pte_alloc(void)
{
return kmem_cache_alloc(kvm_pte_cache, GFP_KERNEL);
}
static void kvmppc_pte_free(pte_t *ptep)
{
kmem_cache_free(kvm_pte_cache, ptep);
}
/* Like pmd_huge() and pmd_large(), but works regardless of config options */
static inline int pmd_is_leaf(pmd_t pmd)
{
return !!(pmd_val(pmd) & _PAGE_PTE);
}
static pmd_t *kvmppc_pmd_alloc(void)
{
return kmem_cache_alloc(kvm_pmd_cache, GFP_KERNEL);
}
static void kvmppc_pmd_free(pmd_t *pmdp)
{
kmem_cache_free(kvm_pmd_cache, pmdp);
}
/* Called with kvm->mmu_lock held */
void kvmppc_unmap_pte(struct kvm *kvm, pte_t *pte, unsigned long gpa,
unsigned int shift,
const struct kvm_memory_slot *memslot,
unsigned int lpid)
{
unsigned long old;
unsigned long gfn = gpa >> PAGE_SHIFT;
unsigned long page_size = PAGE_SIZE;
unsigned long hpa;
old = kvmppc_radix_update_pte(kvm, pte, ~0UL, 0, gpa, shift);
kvmppc_radix_tlbie_page(kvm, gpa, shift, lpid);
/* The following only applies to L1 entries */
if (lpid != kvm->arch.lpid)
return;
if (!memslot) {
memslot = gfn_to_memslot(kvm, gfn);
if (!memslot)
return;
}
if (shift) { /* 1GB or 2MB page */
page_size = 1ul << shift;
if (shift == PMD_SHIFT)
kvm->stat.num_2M_pages--;
else if (shift == PUD_SHIFT)
kvm->stat.num_1G_pages--;
}
gpa &= ~(page_size - 1);
hpa = old & PTE_RPN_MASK;
kvmhv_remove_nest_rmap_range(kvm, memslot, gpa, hpa, page_size);
if ((old & _PAGE_DIRTY) && memslot->dirty_bitmap)
kvmppc_update_dirty_map(memslot, gfn, page_size);
}
/*
* kvmppc_free_p?d are used to free existing page tables, and recursively
* descend and clear and free children.
* Callers are responsible for flushing the PWC.
*
* When page tables are being unmapped/freed as part of page fault path
* (full == false), ptes are not expected. There is code to unmap them
* and emit a warning if encountered, but there may already be data
* corruption due to the unexpected mappings.
*/
static void kvmppc_unmap_free_pte(struct kvm *kvm, pte_t *pte, bool full,
unsigned int lpid)
{
if (full) {
memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
} else {
pte_t *p = pte;
unsigned long it;
for (it = 0; it < PTRS_PER_PTE; ++it, ++p) {
if (pte_val(*p) == 0)
continue;
WARN_ON_ONCE(1);
kvmppc_unmap_pte(kvm, p,
pte_pfn(*p) << PAGE_SHIFT,
PAGE_SHIFT, NULL, lpid);
}
}
kvmppc_pte_free(pte);
}
static void kvmppc_unmap_free_pmd(struct kvm *kvm, pmd_t *pmd, bool full,
unsigned int lpid)
{
unsigned long im;
pmd_t *p = pmd;
for (im = 0; im < PTRS_PER_PMD; ++im, ++p) {
if (!pmd_present(*p))
continue;
if (pmd_is_leaf(*p)) {
if (full) {
pmd_clear(p);
} else {
WARN_ON_ONCE(1);
kvmppc_unmap_pte(kvm, (pte_t *)p,
pte_pfn(*(pte_t *)p) << PAGE_SHIFT,
PMD_SHIFT, NULL, lpid);
}
} else {
pte_t *pte;
pte = pte_offset_map(p, 0);
kvmppc_unmap_free_pte(kvm, pte, full, lpid);
pmd_clear(p);
}
}
kvmppc_pmd_free(pmd);
}
static void kvmppc_unmap_free_pud(struct kvm *kvm, pud_t *pud,
unsigned int lpid)
{
unsigned long iu;
pud_t *p = pud;
for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++p) {
if (!pud_present(*p))
continue;
if (pud_huge(*p)) {
pud_clear(p);
} else {
pmd_t *pmd;
pmd = pmd_offset(p, 0);
kvmppc_unmap_free_pmd(kvm, pmd, true, lpid);
pud_clear(p);
}
}
pud_free(kvm->mm, pud);
}
void kvmppc_free_pgtable_radix(struct kvm *kvm, pgd_t *pgd, unsigned int lpid)
{
unsigned long ig;
for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
pud_t *pud;
if (!pgd_present(*pgd))
continue;
pud = pud_offset(pgd, 0);
kvmppc_unmap_free_pud(kvm, pud, lpid);
pgd_clear(pgd);
}
}
void kvmppc_free_radix(struct kvm *kvm)
{
if (kvm->arch.pgtable) {
kvmppc_free_pgtable_radix(kvm, kvm->arch.pgtable,
kvm->arch.lpid);
pgd_free(kvm->mm, kvm->arch.pgtable);
kvm->arch.pgtable = NULL;
}
}
static void kvmppc_unmap_free_pmd_entry_table(struct kvm *kvm, pmd_t *pmd,
unsigned long gpa, unsigned int lpid)
{
pte_t *pte = pte_offset_kernel(pmd, 0);
/*
* Clearing the pmd entry then flushing the PWC ensures that the pte
* page no longer be cached by the MMU, so can be freed without
* flushing the PWC again.
*/
pmd_clear(pmd);
kvmppc_radix_flush_pwc(kvm, lpid);
kvmppc_unmap_free_pte(kvm, pte, false, lpid);
}
static void kvmppc_unmap_free_pud_entry_table(struct kvm *kvm, pud_t *pud,
unsigned long gpa, unsigned int lpid)
{
pmd_t *pmd = pmd_offset(pud, 0);
/*
* Clearing the pud entry then flushing the PWC ensures that the pmd
* page and any children pte pages will no longer be cached by the MMU,
* so can be freed without flushing the PWC again.
*/
pud_clear(pud);
kvmppc_radix_flush_pwc(kvm, lpid);
kvmppc_unmap_free_pmd(kvm, pmd, false, lpid);
}
/*
* There are a number of bits which may differ between different faults to
* the same partition scope entry. RC bits, in the course of cleaning and
* aging. And the write bit can change, either the access could have been
* upgraded, or a read fault could happen concurrently with a write fault
* that sets those bits first.
*/
#define PTE_BITS_MUST_MATCH (~(_PAGE_WRITE | _PAGE_DIRTY | _PAGE_ACCESSED))
int kvmppc_create_pte(struct kvm *kvm, pgd_t *pgtable, pte_t pte,
unsigned long gpa, unsigned int level,
unsigned long mmu_seq, unsigned int lpid,
unsigned long *rmapp, struct rmap_nested **n_rmap)
{
pgd_t *pgd;
pud_t *pud, *new_pud = NULL;
pmd_t *pmd, *new_pmd = NULL;
pte_t *ptep, *new_ptep = NULL;
int ret;
/* Traverse the guest's 2nd-level tree, allocate new levels needed */
pgd = pgtable + pgd_index(gpa);
pud = NULL;
if (pgd_present(*pgd))
pud = pud_offset(pgd, gpa);
else
new_pud = pud_alloc_one(kvm->mm, gpa);
pmd = NULL;
if (pud && pud_present(*pud) && !pud_huge(*pud))
pmd = pmd_offset(pud, gpa);
else if (level <= 1)
new_pmd = kvmppc_pmd_alloc();
if (level == 0 && !(pmd && pmd_present(*pmd) && !pmd_is_leaf(*pmd)))
new_ptep = kvmppc_pte_alloc();
/* Check if we might have been invalidated; let the guest retry if so */
spin_lock(&kvm->mmu_lock);
ret = -EAGAIN;
if (mmu_notifier_retry(kvm, mmu_seq))
goto out_unlock;
/* Now traverse again under the lock and change the tree */
ret = -ENOMEM;
if (pgd_none(*pgd)) {
if (!new_pud)
goto out_unlock;
pgd_populate(kvm->mm, pgd, new_pud);
new_pud = NULL;
}
pud = pud_offset(pgd, gpa);
if (pud_huge(*pud)) {
unsigned long hgpa = gpa & PUD_MASK;
/* Check if we raced and someone else has set the same thing */
if (level == 2) {
if (pud_raw(*pud) == pte_raw(pte)) {
ret = 0;
goto out_unlock;
}
/* Valid 1GB page here already, add our extra bits */
WARN_ON_ONCE((pud_val(*pud) ^ pte_val(pte)) &
PTE_BITS_MUST_MATCH);
kvmppc_radix_update_pte(kvm, (pte_t *)pud,
0, pte_val(pte), hgpa, PUD_SHIFT);
ret = 0;
goto out_unlock;
}
/*
* If we raced with another CPU which has just put
* a 1GB pte in after we saw a pmd page, try again.
*/
if (!new_pmd) {
ret = -EAGAIN;
goto out_unlock;
}
/* Valid 1GB page here already, remove it */
kvmppc_unmap_pte(kvm, (pte_t *)pud, hgpa, PUD_SHIFT, NULL,
lpid);
}
if (level == 2) {
if (!pud_none(*pud)) {
/*
* There's a page table page here, but we wanted to
* install a large page, so remove and free the page
* table page.
*/
kvmppc_unmap_free_pud_entry_table(kvm, pud, gpa, lpid);
}
kvmppc_radix_set_pte_at(kvm, gpa, (pte_t *)pud, pte);
if (rmapp && n_rmap)
kvmhv_insert_nest_rmap(kvm, rmapp, n_rmap);
ret = 0;
goto out_unlock;
}
if (pud_none(*pud)) {
if (!new_pmd)
goto out_unlock;
pud_populate(kvm->mm, pud, new_pmd);
new_pmd = NULL;
}
pmd = pmd_offset(pud, gpa);
if (pmd_is_leaf(*pmd)) {
unsigned long lgpa = gpa & PMD_MASK;
/* Check if we raced and someone else has set the same thing */
if (level == 1) {
if (pmd_raw(*pmd) == pte_raw(pte)) {
ret = 0;
goto out_unlock;
}
/* Valid 2MB page here already, add our extra bits */
WARN_ON_ONCE((pmd_val(*pmd) ^ pte_val(pte)) &
PTE_BITS_MUST_MATCH);
kvmppc_radix_update_pte(kvm, pmdp_ptep(pmd),
0, pte_val(pte), lgpa, PMD_SHIFT);
ret = 0;
goto out_unlock;
}
/*
* If we raced with another CPU which has just put
* a 2MB pte in after we saw a pte page, try again.
*/
if (!new_ptep) {
ret = -EAGAIN;
goto out_unlock;
}
/* Valid 2MB page here already, remove it */
kvmppc_unmap_pte(kvm, pmdp_ptep(pmd), lgpa, PMD_SHIFT, NULL,
lpid);
}
if (level == 1) {
if (!pmd_none(*pmd)) {
/*
* There's a page table page here, but we wanted to
* install a large page, so remove and free the page
* table page.
*/
kvmppc_unmap_free_pmd_entry_table(kvm, pmd, gpa, lpid);
}
kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte);
if (rmapp && n_rmap)
kvmhv_insert_nest_rmap(kvm, rmapp, n_rmap);
ret = 0;
goto out_unlock;
}
if (pmd_none(*pmd)) {
if (!new_ptep)
goto out_unlock;
pmd_populate(kvm->mm, pmd, new_ptep);
new_ptep = NULL;
}
ptep = pte_offset_kernel(pmd, gpa);
if (pte_present(*ptep)) {
/* Check if someone else set the same thing */
if (pte_raw(*ptep) == pte_raw(pte)) {
ret = 0;
goto out_unlock;
}
/* Valid page here already, add our extra bits */
WARN_ON_ONCE((pte_val(*ptep) ^ pte_val(pte)) &
PTE_BITS_MUST_MATCH);
kvmppc_radix_update_pte(kvm, ptep, 0, pte_val(pte), gpa, 0);
ret = 0;
goto out_unlock;
}
kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte);
if (rmapp && n_rmap)
kvmhv_insert_nest_rmap(kvm, rmapp, n_rmap);
ret = 0;
out_unlock:
spin_unlock(&kvm->mmu_lock);
if (new_pud)
pud_free(kvm->mm, new_pud);
if (new_pmd)
kvmppc_pmd_free(new_pmd);
if (new_ptep)
kvmppc_pte_free(new_ptep);
return ret;
}
bool kvmppc_hv_handle_set_rc(struct kvm *kvm, pgd_t *pgtable, bool writing,
unsigned long gpa, unsigned int lpid)
{
unsigned long pgflags;
unsigned int shift;
pte_t *ptep;
/*
* Need to set an R or C bit in the 2nd-level tables;
* since we are just helping out the hardware here,
* it is sufficient to do what the hardware does.
*/
pgflags = _PAGE_ACCESSED;
if (writing)
pgflags |= _PAGE_DIRTY;
/*
* We are walking the secondary (partition-scoped) page table here.
* We can do this without disabling irq because the Linux MM
* subsystem doesn't do THP splits and collapses on this tree.
*/
ptep = __find_linux_pte(pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && (!writing || pte_write(*ptep))) {
kvmppc_radix_update_pte(kvm, ptep, 0, pgflags, gpa, shift);
return true;
}
return false;
}
int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
unsigned long gpa,
struct kvm_memory_slot *memslot,
bool writing, bool kvm_ro,
pte_t *inserted_pte, unsigned int *levelp)
{
struct kvm *kvm = vcpu->kvm;
struct page *page = NULL;
unsigned long mmu_seq;
unsigned long hva, gfn = gpa >> PAGE_SHIFT;
bool upgrade_write = false;
bool *upgrade_p = &upgrade_write;
pte_t pte, *ptep;
unsigned int shift, level;
int ret;
bool large_enable;
/* used to check for invalidations in progress */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
/*
* Do a fast check first, since __gfn_to_pfn_memslot doesn't
* do it with !atomic && !async, which is how we call it.
* We always ask for write permission since the common case
* is that the page is writable.
*/
hva = gfn_to_hva_memslot(memslot, gfn);
if (!kvm_ro && __get_user_pages_fast(hva, 1, 1, &page) == 1) {
upgrade_write = true;
} else {
unsigned long pfn;
/* Call KVM generic code to do the slow-path check */
pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL,
writing, upgrade_p);
if (is_error_noslot_pfn(pfn))
return -EFAULT;
page = NULL;
if (pfn_valid(pfn)) {
page = pfn_to_page(pfn);
if (PageReserved(page))
page = NULL;
}
}
/*
* Read the PTE from the process' radix tree and use that
* so we get the shift and attribute bits.
*/
local_irq_disable();
ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift);
/*
* If the PTE disappeared temporarily due to a THP
* collapse, just return and let the guest try again.
*/
if (!ptep) {
local_irq_enable();
if (page)
put_page(page);
return RESUME_GUEST;
}
pte = *ptep;
local_irq_enable();
/* If we're logging dirty pages, always map single pages */
large_enable = !(memslot->flags & KVM_MEM_LOG_DIRTY_PAGES);
/* Get pte level from shift/size */
if (large_enable && shift == PUD_SHIFT &&
(gpa & (PUD_SIZE - PAGE_SIZE)) ==
(hva & (PUD_SIZE - PAGE_SIZE))) {
level = 2;
} else if (large_enable && shift == PMD_SHIFT &&
(gpa & (PMD_SIZE - PAGE_SIZE)) ==
(hva & (PMD_SIZE - PAGE_SIZE))) {
level = 1;
} else {
level = 0;
if (shift > PAGE_SHIFT) {
/*
* If the pte maps more than one page, bring over
* bits from the virtual address to get the real
* address of the specific single page we want.
*/
unsigned long rpnmask = (1ul << shift) - PAGE_SIZE;
pte = __pte(pte_val(pte) | (hva & rpnmask));
}
}
pte = __pte(pte_val(pte) | _PAGE_EXEC | _PAGE_ACCESSED);
if (writing || upgrade_write) {
if (pte_val(pte) & _PAGE_WRITE)
pte = __pte(pte_val(pte) | _PAGE_DIRTY);
} else {
pte = __pte(pte_val(pte) & ~(_PAGE_WRITE | _PAGE_DIRTY));
}
/* Allocate space in the tree and write the PTE */
ret = kvmppc_create_pte(kvm, kvm->arch.pgtable, pte, gpa, level,
mmu_seq, kvm->arch.lpid, NULL, NULL);
if (inserted_pte)
*inserted_pte = pte;
if (levelp)
*levelp = level;
if (page) {
if (!ret && (pte_val(pte) & _PAGE_WRITE))
set_page_dirty_lock(page);
put_page(page);
}
/* Increment number of large pages if we (successfully) inserted one */
if (!ret) {
if (level == 1)
kvm->stat.num_2M_pages++;
else if (level == 2)
kvm->stat.num_1G_pages++;
}
return ret;
}
int kvmppc_book3s_radix_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned long ea, unsigned long dsisr)
{
struct kvm *kvm = vcpu->kvm;
unsigned long gpa, gfn;
struct kvm_memory_slot *memslot;
long ret;
bool writing = !!(dsisr & DSISR_ISSTORE);
bool kvm_ro = false;
/* Check for unusual errors */
if (dsisr & DSISR_UNSUPP_MMU) {
pr_err("KVM: Got unsupported MMU fault\n");
return -EFAULT;
}
if (dsisr & DSISR_BADACCESS) {
/* Reflect to the guest as DSI */
pr_err("KVM: Got radix HV page fault with DSISR=%lx\n", dsisr);
kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
return RESUME_GUEST;
}
/* Translate the logical address */
gpa = vcpu->arch.fault_gpa & ~0xfffUL;
gpa &= ~0xF000000000000000ul;
gfn = gpa >> PAGE_SHIFT;
if (!(dsisr & DSISR_PRTABLE_FAULT))
gpa |= ea & 0xfff;
/* Get the corresponding memslot */
memslot = gfn_to_memslot(kvm, gfn);
/* No memslot means it's an emulated MMIO region */
if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID)) {
if (dsisr & (DSISR_PRTABLE_FAULT | DSISR_BADACCESS |
DSISR_SET_RC)) {
/*
* Bad address in guest page table tree, or other
* unusual error - reflect it to the guest as DSI.
*/
kvmppc_core_queue_data_storage(vcpu, ea, dsisr);
return RESUME_GUEST;
}
return kvmppc_hv_emulate_mmio(run, vcpu, gpa, ea, writing);
}
if (memslot->flags & KVM_MEM_READONLY) {
if (writing) {
/* give the guest a DSI */
kvmppc_core_queue_data_storage(vcpu, ea, DSISR_ISSTORE |
DSISR_PROTFAULT);
return RESUME_GUEST;
}
kvm_ro = true;
}
/* Failed to set the reference/change bits */
if (dsisr & DSISR_SET_RC) {
spin_lock(&kvm->mmu_lock);
if (kvmppc_hv_handle_set_rc(kvm, kvm->arch.pgtable,
writing, gpa, kvm->arch.lpid))
dsisr &= ~DSISR_SET_RC;
spin_unlock(&kvm->mmu_lock);
if (!(dsisr & (DSISR_BAD_FAULT_64S | DSISR_NOHPTE |
DSISR_PROTFAULT | DSISR_SET_RC)))
return RESUME_GUEST;
}
/* Try to insert a pte */
ret = kvmppc_book3s_instantiate_page(vcpu, gpa, memslot, writing,
kvm_ro, NULL, NULL);
if (ret == 0 || ret == -EAGAIN)
ret = RESUME_GUEST;
return ret;
}
/* Called with kvm->mmu_lock held */
int kvm_unmap_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long gfn)
{
pte_t *ptep;
unsigned long gpa = gfn << PAGE_SHIFT;
unsigned int shift;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep))
kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
kvm->arch.lpid);
return 0;
}
/* Called with kvm->mmu_lock held */
int kvm_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long gfn)
{
pte_t *ptep;
unsigned long gpa = gfn << PAGE_SHIFT;
unsigned int shift;
int ref = 0;
unsigned long old, *rmapp;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
gpa, shift);
/* XXX need to flush tlb here? */
/* Also clear bit in ptes in shadow pgtable for nested guests */
rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
kvmhv_update_nest_rmap_rc_list(kvm, rmapp, _PAGE_ACCESSED, 0,
old & PTE_RPN_MASK,
1UL << shift);
ref = 1;
}
return ref;
}
/* Called with kvm->mmu_lock held */
int kvm_test_age_radix(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long gfn)
{
pte_t *ptep;
unsigned long gpa = gfn << PAGE_SHIFT;
unsigned int shift;
int ref = 0;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep))
ref = 1;
return ref;
}
/* Returns the number of PAGE_SIZE pages that are dirty */
static int kvm_radix_test_clear_dirty(struct kvm *kvm,
struct kvm_memory_slot *memslot, int pagenum)
{
unsigned long gfn = memslot->base_gfn + pagenum;
unsigned long gpa = gfn << PAGE_SHIFT;
pte_t *ptep;
unsigned int shift;
int ret = 0;
unsigned long old, *rmapp;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_dirty(*ptep)) {
ret = 1;
if (shift)
ret = 1 << (shift - PAGE_SHIFT);
spin_lock(&kvm->mmu_lock);
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
gpa, shift);
kvmppc_radix_tlbie_page(kvm, gpa, shift, kvm->arch.lpid);
/* Also clear bit in ptes in shadow pgtable for nested guests */
rmapp = &memslot->arch.rmap[gfn - memslot->base_gfn];
kvmhv_update_nest_rmap_rc_list(kvm, rmapp, _PAGE_DIRTY, 0,
old & PTE_RPN_MASK,
1UL << shift);
spin_unlock(&kvm->mmu_lock);
}
return ret;
}
long kvmppc_hv_get_dirty_log_radix(struct kvm *kvm,
struct kvm_memory_slot *memslot, unsigned long *map)
{
unsigned long i, j;
int npages;
for (i = 0; i < memslot->npages; i = j) {
npages = kvm_radix_test_clear_dirty(kvm, memslot, i);
/*
* Note that if npages > 0 then i must be a multiple of npages,
* since huge pages are only used to back the guest at guest
* real addresses that are a multiple of their size.
* Since we have at most one PTE covering any given guest
* real address, if npages > 1 we can skip to i + npages.
*/
j = i + 1;
if (npages) {
set_dirty_bits(map, i, npages);
j = i + npages;
}
}
return 0;
}
void kvmppc_radix_flush_memslot(struct kvm *kvm,
const struct kvm_memory_slot *memslot)
{
unsigned long n;
pte_t *ptep;
unsigned long gpa;
unsigned int shift;
gpa = memslot->base_gfn << PAGE_SHIFT;
spin_lock(&kvm->mmu_lock);
for (n = memslot->npages; n; --n) {
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep))
kvmppc_unmap_pte(kvm, ptep, gpa, shift, memslot,
kvm->arch.lpid);
gpa += PAGE_SIZE;
}
spin_unlock(&kvm->mmu_lock);
}
static void add_rmmu_ap_encoding(struct kvm_ppc_rmmu_info *info,
int psize, int *indexp)
{
if (!mmu_psize_defs[psize].shift)
return;
info->ap_encodings[*indexp] = mmu_psize_defs[psize].shift |
(mmu_psize_defs[psize].ap << 29);
++(*indexp);
}
int kvmhv_get_rmmu_info(struct kvm *kvm, struct kvm_ppc_rmmu_info *info)
{
int i;
if (!radix_enabled())
return -EINVAL;
memset(info, 0, sizeof(*info));
/* 4k page size */
info->geometries[0].page_shift = 12;
info->geometries[0].level_bits[0] = 9;
for (i = 1; i < 4; ++i)
info->geometries[0].level_bits[i] = p9_supported_radix_bits[i];
/* 64k page size */
info->geometries[1].page_shift = 16;
for (i = 0; i < 4; ++i)
info->geometries[1].level_bits[i] = p9_supported_radix_bits[i];
i = 0;
add_rmmu_ap_encoding(info, MMU_PAGE_4K, &i);
add_rmmu_ap_encoding(info, MMU_PAGE_64K, &i);
add_rmmu_ap_encoding(info, MMU_PAGE_2M, &i);
add_rmmu_ap_encoding(info, MMU_PAGE_1G, &i);
return 0;
}
int kvmppc_init_vm_radix(struct kvm *kvm)
{
kvm->arch.pgtable = pgd_alloc(kvm->mm);
if (!kvm->arch.pgtable)
return -ENOMEM;
return 0;
}
static void pte_ctor(void *addr)
{
memset(addr, 0, RADIX_PTE_TABLE_SIZE);
}
static void pmd_ctor(void *addr)
{
memset(addr, 0, RADIX_PMD_TABLE_SIZE);
}
struct debugfs_radix_state {
struct kvm *kvm;
struct mutex mutex;
unsigned long gpa;
int lpid;
int chars_left;
int buf_index;
char buf[128];
u8 hdr;
};
static int debugfs_radix_open(struct inode *inode, struct file *file)
{
struct kvm *kvm = inode->i_private;
struct debugfs_radix_state *p;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
kvm_get_kvm(kvm);
p->kvm = kvm;
mutex_init(&p->mutex);
file->private_data = p;
return nonseekable_open(inode, file);
}
static int debugfs_radix_release(struct inode *inode, struct file *file)
{
struct debugfs_radix_state *p = file->private_data;
kvm_put_kvm(p->kvm);
kfree(p);
return 0;
}
static ssize_t debugfs_radix_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
struct debugfs_radix_state *p = file->private_data;
ssize_t ret, r;
unsigned long n;
struct kvm *kvm;
unsigned long gpa;
pgd_t *pgt;
struct kvm_nested_guest *nested;
pgd_t pgd, *pgdp;
pud_t pud, *pudp;
pmd_t pmd, *pmdp;
pte_t *ptep;
int shift;
unsigned long pte;
kvm = p->kvm;
if (!kvm_is_radix(kvm))
return 0;
ret = mutex_lock_interruptible(&p->mutex);
if (ret)
return ret;
if (p->chars_left) {
n = p->chars_left;
if (n > len)
n = len;
r = copy_to_user(buf, p->buf + p->buf_index, n);
n -= r;
p->chars_left -= n;
p->buf_index += n;
buf += n;
len -= n;
ret = n;
if (r) {
if (!n)
ret = -EFAULT;
goto out;
}
}
gpa = p->gpa;
nested = NULL;
pgt = NULL;
while (len != 0 && p->lpid >= 0) {
if (gpa >= RADIX_PGTABLE_RANGE) {
gpa = 0;
pgt = NULL;
if (nested) {
kvmhv_put_nested(nested);
nested = NULL;
}
p->lpid = kvmhv_nested_next_lpid(kvm, p->lpid);
p->hdr = 0;
if (p->lpid < 0)
break;
}
if (!pgt) {
if (p->lpid == 0) {
pgt = kvm->arch.pgtable;
} else {
nested = kvmhv_get_nested(kvm, p->lpid, false);
if (!nested) {
gpa = RADIX_PGTABLE_RANGE;
continue;
}
pgt = nested->shadow_pgtable;
}
}
n = 0;
if (!p->hdr) {
if (p->lpid > 0)
n = scnprintf(p->buf, sizeof(p->buf),
"\nNested LPID %d: ", p->lpid);
n += scnprintf(p->buf + n, sizeof(p->buf) - n,
"pgdir: %lx\n", (unsigned long)pgt);
p->hdr = 1;
goto copy;
}
pgdp = pgt + pgd_index(gpa);
pgd = READ_ONCE(*pgdp);
if (!(pgd_val(pgd) & _PAGE_PRESENT)) {
gpa = (gpa & PGDIR_MASK) + PGDIR_SIZE;
continue;
}
pudp = pud_offset(&pgd, gpa);
pud = READ_ONCE(*pudp);
if (!(pud_val(pud) & _PAGE_PRESENT)) {
gpa = (gpa & PUD_MASK) + PUD_SIZE;
continue;
}
if (pud_val(pud) & _PAGE_PTE) {
pte = pud_val(pud);
shift = PUD_SHIFT;
goto leaf;
}
pmdp = pmd_offset(&pud, gpa);
pmd = READ_ONCE(*pmdp);
if (!(pmd_val(pmd) & _PAGE_PRESENT)) {
gpa = (gpa & PMD_MASK) + PMD_SIZE;
continue;
}
if (pmd_val(pmd) & _PAGE_PTE) {
pte = pmd_val(pmd);
shift = PMD_SHIFT;
goto leaf;
}
ptep = pte_offset_kernel(&pmd, gpa);
pte = pte_val(READ_ONCE(*ptep));
if (!(pte & _PAGE_PRESENT)) {
gpa += PAGE_SIZE;
continue;
}
shift = PAGE_SHIFT;
leaf:
n = scnprintf(p->buf, sizeof(p->buf),
" %lx: %lx %d\n", gpa, pte, shift);
gpa += 1ul << shift;
copy:
p->chars_left = n;
if (n > len)
n = len;
r = copy_to_user(buf, p->buf, n);
n -= r;
p->chars_left -= n;
p->buf_index = n;
buf += n;
len -= n;
ret += n;
if (r) {
if (!ret)
ret = -EFAULT;
break;
}
}
p->gpa = gpa;
if (nested)
kvmhv_put_nested(nested);
out:
mutex_unlock(&p->mutex);
return ret;
}
static ssize_t debugfs_radix_write(struct file *file, const char __user *buf,
size_t len, loff_t *ppos)
{
return -EACCES;
}
static const struct file_operations debugfs_radix_fops = {
.owner = THIS_MODULE,
.open = debugfs_radix_open,
.release = debugfs_radix_release,
.read = debugfs_radix_read,
.write = debugfs_radix_write,
.llseek = generic_file_llseek,
};
void kvmhv_radix_debugfs_init(struct kvm *kvm)
{
kvm->arch.radix_dentry = debugfs_create_file("radix", 0400,
kvm->arch.debugfs_dir, kvm,
&debugfs_radix_fops);
}
int kvmppc_radix_init(void)
{
unsigned long size = sizeof(void *) << RADIX_PTE_INDEX_SIZE;
kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
if (!kvm_pte_cache)
return -ENOMEM;
size = sizeof(void *) << RADIX_PMD_INDEX_SIZE;
kvm_pmd_cache = kmem_cache_create("kvm-pmd", size, size, 0, pmd_ctor);
if (!kvm_pmd_cache) {
kmem_cache_destroy(kvm_pte_cache);
return -ENOMEM;
}
return 0;
}
void kvmppc_radix_exit(void)
{
kmem_cache_destroy(kvm_pte_cache);
kmem_cache_destroy(kvm_pmd_cache);
}
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