linux/arch/powerpc/kvm/book3s_64_mmu_radix.c
Paul Mackerras 18c3640cef KVM: PPC: Book3S HV: Add infrastructure for running HPT guests on radix host
This sets up the machinery for switching a guest between HPT (hashed
page table) and radix MMU modes, so that in future we can run a HPT
guest on a radix host on POWER9 machines.

* The KVM_PPC_CONFIGURE_V3_MMU ioctl can now specify either HPT or
  radix mode, on a radix host.

* The KVM_CAP_PPC_MMU_HASH_V3 capability now returns 1 on POWER9
  with HV KVM on a radix host.

* The KVM_PPC_GET_SMMU_INFO returns information about the HPT MMU on a
  radix host.

* The KVM_PPC_ALLOCATE_HTAB ioctl on a radix host will switch the
  guest to HPT mode and allocate a HPT.

* For simplicity, we now allocate the rmap array for each memslot,
  even on a radix host, since it will be needed if the guest switches
  to HPT mode.

* Since we cannot yet run a HPT guest on a radix host, the KVM_RUN
  ioctl will return an EINVAL error in that case.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-11-01 15:36:28 +11:00

687 lines
17 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 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 <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 };
int kvmppc_mmu_radix_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
struct kvmppc_pte *gpte, bool data, bool iswrite)
{
struct kvm *kvm = vcpu->kvm;
u32 pid;
int ret, level, ps;
__be64 prte, rpte;
unsigned long ptbl;
unsigned long root, pte, index;
unsigned long rts, bits, offset;
unsigned long gpa;
unsigned long proc_tbl_size;
/* Work out effective PID */
switch (eaddr >> 62) {
case 0:
pid = vcpu->arch.pid;
break;
case 3:
pid = 0;
break;
default:
return -EINVAL;
}
proc_tbl_size = 1 << ((kvm->arch.process_table & PRTS_MASK) + 12);
if (pid * 16 >= proc_tbl_size)
return -EINVAL;
/* Read partition table to find root of tree for effective PID */
ptbl = (kvm->arch.process_table & PRTB_MASK) + (pid * 16);
ret = kvm_read_guest(kvm, ptbl, &prte, sizeof(prte));
if (ret)
return ret;
root = be64_to_cpu(prte);
rts = ((root & RTS1_MASK) >> (RTS1_SHIFT - 3)) |
((root & RTS2_MASK) >> RTS2_SHIFT);
bits = root & RPDS_MASK;
root = root & RPDB_MASK;
/* P9 DD1 interprets RTS (radix tree size) differently */
offset = rts + 31;
if (cpu_has_feature(CPU_FTR_POWER9_DD1))
offset -= 3;
/* current implementations only support 52-bit space */
if (offset != 52)
return -EINVAL;
for (level = 3; level >= 0; --level) {
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 (root & ((1UL << (bits + 3)) - 1))
return -EINVAL;
ret = kvm_read_guest(kvm, root + index * 8,
&rpte, sizeof(rpte));
if (ret)
return ret;
pte = __be64_to_cpu(rpte);
if (!(pte & _PAGE_PRESENT))
return -ENOENT;
if (pte & _PAGE_PTE)
break;
bits = pte & 0x1f;
root = pte & 0x0fffffffffffff00ul;
}
/* need a leaf at lowest level; 512GB pages not supported */
if (level < 0 || level == 3)
return -EINVAL;
/* 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->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);
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;
}
#ifdef CONFIG_PPC_64K_PAGES
#define MMU_BASE_PSIZE MMU_PAGE_64K
#else
#define MMU_BASE_PSIZE MMU_PAGE_4K
#endif
static void kvmppc_radix_tlbie_page(struct kvm *kvm, unsigned long addr,
unsigned int pshift)
{
int psize = MMU_BASE_PSIZE;
if (pshift >= PMD_SHIFT)
psize = MMU_PAGE_2M;
addr &= ~0xfffUL;
addr |= mmu_psize_defs[psize].ap << 5;
asm volatile("ptesync": : :"memory");
asm volatile(PPC_TLBIE_5(%0, %1, 0, 0, 1)
: : "r" (addr), "r" (kvm->arch.lpid) : "memory");
asm volatile("ptesync": : :"memory");
}
unsigned long kvmppc_radix_update_pte(struct kvm *kvm, pte_t *ptep,
unsigned long clr, unsigned long set,
unsigned long addr, unsigned int shift)
{
unsigned long old = 0;
if (!(clr & _PAGE_PRESENT) && cpu_has_feature(CPU_FTR_POWER9_DD1) &&
pte_present(*ptep)) {
/* have to invalidate it first */
old = __radix_pte_update(ptep, _PAGE_PRESENT, 0);
kvmppc_radix_tlbie_page(kvm, addr, shift);
set |= _PAGE_PRESENT;
old &= _PAGE_PRESENT;
}
return __radix_pte_update(ptep, clr, set) | old;
}
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 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);
}
static int kvmppc_create_pte(struct kvm *kvm, pte_t pte, unsigned long gpa,
unsigned int level, unsigned long mmu_seq)
{
pgd_t *pgd;
pud_t *pud, *new_pud = NULL;
pmd_t *pmd, *new_pmd = NULL;
pte_t *ptep, *new_ptep = NULL;
unsigned long old;
int ret;
/* Traverse the guest's 2nd-level tree, allocate new levels needed */
pgd = kvm->arch.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))
pmd = pmd_offset(pud, gpa);
else
new_pmd = pmd_alloc_one(kvm->mm, gpa);
if (level == 0 && !(pmd && pmd_present(*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_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_large(*pmd)) {
/* Someone else has instantiated a large page here; retry */
ret = -EAGAIN;
goto out_unlock;
}
if (level == 1 && !pmd_none(*pmd)) {
/*
* There's a page table page here, but we wanted
* to install a large page. Tell the caller and let
* it try installing a normal page if it wants.
*/
ret = -EBUSY;
goto out_unlock;
}
if (level == 0) {
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)) {
/* PTE was previously valid, so invalidate it */
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT,
0, gpa, 0);
kvmppc_radix_tlbie_page(kvm, gpa, 0);
if (old & _PAGE_DIRTY)
mark_page_dirty(kvm, gpa >> PAGE_SHIFT);
}
kvmppc_radix_set_pte_at(kvm, gpa, ptep, pte);
} else {
kvmppc_radix_set_pte_at(kvm, gpa, pmdp_ptep(pmd), pte);
}
ret = 0;
out_unlock:
spin_unlock(&kvm->mmu_lock);
if (new_pud)
pud_free(kvm->mm, new_pud);
if (new_pmd)
pmd_free(kvm->mm, new_pmd);
if (new_ptep)
kvmppc_pte_free(new_ptep);
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 mmu_seq, pte_size;
unsigned long gpa, gfn, hva, pfn;
struct kvm_memory_slot *memslot;
struct page *page = NULL, *pages[1];
long ret, npages, ok;
unsigned int writing;
struct vm_area_struct *vma;
unsigned long flags;
pte_t pte, *ptep;
unsigned long pgflags;
unsigned int shift, level;
/* 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 and get the page */
gpa = vcpu->arch.fault_gpa & ~0xfffUL;
gpa &= ~0xF000000000000000ul;
gfn = gpa >> PAGE_SHIFT;
if (!(dsisr & DSISR_PRTABLE_FAULT))
gpa |= ea & 0xfff;
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,
dsisr & DSISR_ISSTORE);
}
/* used to check for invalidations in progress */
mmu_seq = kvm->mmu_notifier_seq;
smp_rmb();
writing = (dsisr & DSISR_ISSTORE) != 0;
hva = gfn_to_hva_memslot(memslot, gfn);
if (dsisr & DSISR_SET_RC) {
/*
* Need to set an R or C bit in the 2nd-level tables;
* if the relevant bits aren't already set in the linux
* page tables, fall through to do the gup_fast to
* set them in the linux page tables too.
*/
ok = 0;
pgflags = _PAGE_ACCESSED;
if (writing)
pgflags |= _PAGE_DIRTY;
local_irq_save(flags);
ptep = find_current_mm_pte(current->mm->pgd, hva, NULL, NULL);
if (ptep) {
pte = READ_ONCE(*ptep);
if (pte_present(pte) &&
(pte_val(pte) & pgflags) == pgflags)
ok = 1;
}
local_irq_restore(flags);
if (ok) {
spin_lock(&kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) {
spin_unlock(&kvm->mmu_lock);
return RESUME_GUEST;
}
/*
* We are walking the secondary page table here. We can do this
* without disabling irq.
*/
ptep = __find_linux_pte(kvm->arch.pgtable,
gpa, NULL, &shift);
if (ptep && pte_present(*ptep)) {
kvmppc_radix_update_pte(kvm, ptep, 0, pgflags,
gpa, shift);
spin_unlock(&kvm->mmu_lock);
return RESUME_GUEST;
}
spin_unlock(&kvm->mmu_lock);
}
}
ret = -EFAULT;
pfn = 0;
pte_size = PAGE_SIZE;
pgflags = _PAGE_READ | _PAGE_EXEC;
level = 0;
npages = get_user_pages_fast(hva, 1, writing, pages);
if (npages < 1) {
/* Check if it's an I/O mapping */
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, hva);
if (vma && vma->vm_start <= hva && hva < vma->vm_end &&
(vma->vm_flags & VM_PFNMAP)) {
pfn = vma->vm_pgoff +
((hva - vma->vm_start) >> PAGE_SHIFT);
pgflags = pgprot_val(vma->vm_page_prot);
}
up_read(&current->mm->mmap_sem);
if (!pfn)
return -EFAULT;
} else {
page = pages[0];
pfn = page_to_pfn(page);
if (PageHuge(page)) {
page = compound_head(page);
pte_size <<= compound_order(page);
/* See if we can insert a 2MB large-page PTE here */
if (pte_size >= PMD_SIZE &&
(gpa & PMD_MASK & PAGE_MASK) ==
(hva & PMD_MASK & PAGE_MASK)) {
level = 1;
pfn &= ~((PMD_SIZE >> PAGE_SHIFT) - 1);
}
}
/* See if we can provide write access */
if (writing) {
/*
* We assume gup_fast has set dirty on the host PTE.
*/
pgflags |= _PAGE_WRITE;
} else {
local_irq_save(flags);
ptep = find_current_mm_pte(current->mm->pgd,
hva, NULL, NULL);
if (ptep && pte_write(*ptep) && pte_dirty(*ptep))
pgflags |= _PAGE_WRITE;
local_irq_restore(flags);
}
}
/*
* Compute the PTE value that we need to insert.
*/
pgflags |= _PAGE_PRESENT | _PAGE_PTE | _PAGE_ACCESSED;
if (pgflags & _PAGE_WRITE)
pgflags |= _PAGE_DIRTY;
pte = pfn_pte(pfn, __pgprot(pgflags));
/* Allocate space in the tree and write the PTE */
ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
if (ret == -EBUSY) {
/*
* There's already a PMD where wanted to install a large page;
* for now, fall back to installing a small page.
*/
level = 0;
pfn |= gfn & ((PMD_SIZE >> PAGE_SHIFT) - 1);
pte = pfn_pte(pfn, __pgprot(pgflags));
ret = kvmppc_create_pte(kvm, pte, gpa, level, mmu_seq);
}
if (ret == 0 || ret == -EAGAIN)
ret = RESUME_GUEST;
if (page) {
/*
* We drop pages[0] here, not page because page might
* have been set to the head page of a compound, but
* we have to drop the reference on the correct tail
* page to match the get inside gup()
*/
put_page(pages[0]);
}
return ret;
}
/* Called with kvm->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;
unsigned long old;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep)) {
old = kvmppc_radix_update_pte(kvm, ptep, _PAGE_PRESENT, 0,
gpa, shift);
kvmppc_radix_tlbie_page(kvm, gpa, shift);
if ((old & _PAGE_DIRTY) && memslot->dirty_bitmap) {
unsigned long npages = 1;
if (shift)
npages = 1ul << (shift - PAGE_SHIFT);
kvmppc_update_dirty_map(memslot, gfn, npages);
}
}
return 0;
}
/* Called with kvm->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;
ptep = __find_linux_pte(kvm->arch.pgtable, gpa, NULL, &shift);
if (ptep && pte_present(*ptep) && pte_young(*ptep)) {
kvmppc_radix_update_pte(kvm, ptep, _PAGE_ACCESSED, 0,
gpa, shift);
/* XXX need to flush tlb here? */
ref = 1;
}
return ref;
}
/* Called with kvm->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;
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);
kvmppc_radix_update_pte(kvm, ptep, _PAGE_DIRTY, 0,
gpa, shift);
kvmppc_radix_tlbie_page(kvm, gpa, shift);
}
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);
i = j + npages;
}
}
return 0;
}
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;
}
void kvmppc_free_radix(struct kvm *kvm)
{
unsigned long ig, iu, im;
pte_t *pte;
pmd_t *pmd;
pud_t *pud;
pgd_t *pgd;
if (!kvm->arch.pgtable)
return;
pgd = kvm->arch.pgtable;
for (ig = 0; ig < PTRS_PER_PGD; ++ig, ++pgd) {
if (!pgd_present(*pgd))
continue;
pud = pud_offset(pgd, 0);
for (iu = 0; iu < PTRS_PER_PUD; ++iu, ++pud) {
if (!pud_present(*pud))
continue;
pmd = pmd_offset(pud, 0);
for (im = 0; im < PTRS_PER_PMD; ++im, ++pmd) {
if (pmd_huge(*pmd)) {
pmd_clear(pmd);
continue;
}
if (!pmd_present(*pmd))
continue;
pte = pte_offset_map(pmd, 0);
memset(pte, 0, sizeof(long) << PTE_INDEX_SIZE);
kvmppc_pte_free(pte);
pmd_clear(pmd);
}
pmd_free(kvm->mm, pmd_offset(pud, 0));
pud_clear(pud);
}
pud_free(kvm->mm, pud_offset(pgd, 0));
pgd_clear(pgd);
}
pgd_free(kvm->mm, kvm->arch.pgtable);
kvm->arch.pgtable = NULL;
}
static void pte_ctor(void *addr)
{
memset(addr, 0, PTE_TABLE_SIZE);
}
int kvmppc_radix_init(void)
{
unsigned long size = sizeof(void *) << PTE_INDEX_SIZE;
kvm_pte_cache = kmem_cache_create("kvm-pte", size, size, 0, pte_ctor);
if (!kvm_pte_cache)
return -ENOMEM;
return 0;
}
void kvmppc_radix_exit(void)
{
kmem_cache_destroy(kvm_pte_cache);
}