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KVM: PPC: Keep page physical addresses in per-slot arrays
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This allocates an array for each memory slot that is added to store
the physical addresses of the pages in the slot.  This array is
vmalloc'd and accessed in kvmppc_h_enter using real_vmalloc_addr().
This allows us to remove the ram_pginfo field from the kvm_arch
struct, and removes the 64GB guest RAM limit that we had.

We use the low-order bits of the array entries to store a flag
indicating that we have done get_page on the corresponding page,
and therefore need to call put_page when we are finished with the
page.  Currently this is set for all pages except those in our
special RMO regions.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
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Paul Mackerras authored and Avi Kivity committed Mar 5, 2012
1 parent 8936dda commit b2b2f16
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Showing 4 changed files with 107 additions and 75 deletions.
9 changes: 6 additions & 3 deletions arch/powerpc/include/asm/kvm_host.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,7 @@
#define KVM_MEMORY_SLOTS 32
/* memory slots that does not exposed to userspace */
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_MEM_SLOTS_NUM (KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)

#ifdef CONFIG_KVM_MMIO
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
Expand Down Expand Up @@ -175,25 +176,27 @@ struct revmap_entry {
unsigned long guest_rpte;
};

/* Low-order bits in kvm->arch.slot_phys[][] */
#define KVMPPC_GOT_PAGE 0x80

struct kvm_arch {
#ifdef CONFIG_KVM_BOOK3S_64_HV
unsigned long hpt_virt;
struct revmap_entry *revmap;
unsigned long ram_npages;
unsigned long ram_psize;
unsigned long ram_porder;
struct kvmppc_pginfo *ram_pginfo;
unsigned int lpid;
unsigned int host_lpid;
unsigned long host_lpcr;
unsigned long sdr1;
unsigned long host_sdr1;
int tlbie_lock;
int n_rma_pages;
unsigned long lpcr;
unsigned long rmor;
struct kvmppc_rma_info *rma;
struct list_head spapr_tce_tables;
unsigned long *slot_phys[KVM_MEM_SLOTS_NUM];
int slot_npages[KVM_MEM_SLOTS_NUM];
unsigned short last_vcpu[NR_CPUS];
struct kvmppc_vcore *vcores[KVM_MAX_VCORES];
#endif /* CONFIG_KVM_BOOK3S_64_HV */
Expand Down
18 changes: 9 additions & 9 deletions arch/powerpc/kvm/book3s_64_mmu_hv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -98,16 +98,16 @@ void kvmppc_free_hpt(struct kvm *kvm)
void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
{
unsigned long i;
unsigned long npages = kvm->arch.ram_npages;
unsigned long pfn;
unsigned long npages;
unsigned long pa;
unsigned long *hpte;
unsigned long hash;
unsigned long porder = kvm->arch.ram_porder;
struct revmap_entry *rev;
struct kvmppc_pginfo *pginfo = kvm->arch.ram_pginfo;
unsigned long *physp;

if (!pginfo)
return;
physp = kvm->arch.slot_phys[mem->slot];
npages = kvm->arch.slot_npages[mem->slot];

/* VRMA can't be > 1TB */
if (npages > 1ul << (40 - porder))
Expand All @@ -117,9 +117,10 @@ void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
npages = HPT_NPTEG;

for (i = 0; i < npages; ++i) {
pfn = pginfo[i].pfn;
if (!pfn)
pa = physp[i];
if (!pa)
break;
pa &= PAGE_MASK;
/* can't use hpt_hash since va > 64 bits */
hash = (i ^ (VRMA_VSID ^ (VRMA_VSID << 25))) & HPT_HASH_MASK;
/*
Expand All @@ -131,8 +132,7 @@ void kvmppc_map_vrma(struct kvm *kvm, struct kvm_userspace_memory_region *mem)
hash = (hash << 3) + 7;
hpte = (unsigned long *) (kvm->arch.hpt_virt + (hash << 4));
/* HPTE low word - RPN, protection, etc. */
hpte[1] = (pfn << PAGE_SHIFT) | HPTE_R_R | HPTE_R_C |
HPTE_R_M | PP_RWXX;
hpte[1] = pa | HPTE_R_R | HPTE_R_C | HPTE_R_M | PP_RWXX;
smp_wmb();
hpte[0] = HPTE_V_1TB_SEG | (VRMA_VSID << (40 - 16)) |
(i << (VRMA_PAGE_ORDER - 16)) | HPTE_V_BOLTED |
Expand Down
114 changes: 55 additions & 59 deletions arch/powerpc/kvm/book3s_hv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -50,14 +50,6 @@
#include <linux/vmalloc.h>
#include <linux/highmem.h>

/*
* For now, limit memory to 64GB and require it to be large pages.
* This value is chosen because it makes the ram_pginfo array be
* 64kB in size, which is about as large as we want to be trying
* to allocate with kmalloc.
*/
#define MAX_MEM_ORDER 36

#define LARGE_PAGE_ORDER 24 /* 16MB pages */

/* #define EXIT_DEBUG */
Expand Down Expand Up @@ -147,10 +139,12 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
unsigned long vcpuid, unsigned long vpa)
{
struct kvm *kvm = vcpu->kvm;
unsigned long pg_index, ra, len;
unsigned long gfn, pg_index, ra, len;
unsigned long pg_offset;
void *va;
struct kvm_vcpu *tvcpu;
struct kvm_memory_slot *memslot;
unsigned long *physp;

tvcpu = kvmppc_find_vcpu(kvm, vcpuid);
if (!tvcpu)
Expand All @@ -164,14 +158,20 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
if (vpa & 0x7f)
return H_PARAMETER;
/* registering new area; convert logical addr to real */
pg_index = vpa >> kvm->arch.ram_porder;
pg_offset = vpa & (kvm->arch.ram_psize - 1);
if (pg_index >= kvm->arch.ram_npages)
gfn = vpa >> PAGE_SHIFT;
memslot = gfn_to_memslot(kvm, gfn);
if (!memslot || !(memslot->flags & KVM_MEMSLOT_INVALID))
return H_PARAMETER;
physp = kvm->arch.slot_phys[memslot->id];
if (!physp)
return H_PARAMETER;
if (kvm->arch.ram_pginfo[pg_index].pfn == 0)
pg_index = (gfn - memslot->base_gfn) >>
(kvm->arch.ram_porder - PAGE_SHIFT);
pg_offset = vpa & (kvm->arch.ram_psize - 1);
ra = physp[pg_index];
if (!ra)
return H_PARAMETER;
ra = kvm->arch.ram_pginfo[pg_index].pfn << PAGE_SHIFT;
ra |= pg_offset;
ra = (ra & PAGE_MASK) | pg_offset;
va = __va(ra);
if (flags <= 1)
len = *(unsigned short *)(va + 4);
Expand Down Expand Up @@ -1075,12 +1075,11 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem)
{
unsigned long psize, porder;
unsigned long i, npages, totalpages;
unsigned long pg_ix;
struct kvmppc_pginfo *pginfo;
unsigned long i, npages;
unsigned long hva;
struct kvmppc_rma_info *ri = NULL;
struct page *page;
unsigned long *phys;

/* For now, only allow 16MB pages */
porder = LARGE_PAGE_ORDER;
Expand All @@ -1092,20 +1091,21 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
return -EINVAL;
}

/* Allocate a slot_phys array */
npages = mem->memory_size >> porder;
totalpages = (mem->guest_phys_addr + mem->memory_size) >> porder;

/* More memory than we have space to track? */
if (totalpages > (1ul << (MAX_MEM_ORDER - LARGE_PAGE_ORDER)))
return -EINVAL;
phys = kvm->arch.slot_phys[mem->slot];
if (!phys) {
phys = vzalloc(npages * sizeof(unsigned long));
if (!phys)
return -ENOMEM;
kvm->arch.slot_phys[mem->slot] = phys;
kvm->arch.slot_npages[mem->slot] = npages;
}

/* Do we already have an RMA registered? */
if (mem->guest_phys_addr == 0 && kvm->arch.rma)
return -EINVAL;

if (totalpages > kvm->arch.ram_npages)
kvm->arch.ram_npages = totalpages;

/* Is this one of our preallocated RMAs? */
if (mem->guest_phys_addr == 0) {
struct vm_area_struct *vma;
Expand Down Expand Up @@ -1138,7 +1138,6 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
}
atomic_inc(&ri->use_count);
kvm->arch.rma = ri;
kvm->arch.n_rma_pages = rma_size >> porder;

/* Update LPCR and RMOR */
lpcr = kvm->arch.lpcr;
Expand All @@ -1162,12 +1161,9 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
ri->base_pfn << PAGE_SHIFT, rma_size, lpcr);
}

pg_ix = mem->guest_phys_addr >> porder;
pginfo = kvm->arch.ram_pginfo + pg_ix;
for (i = 0; i < npages; ++i, ++pg_ix) {
if (ri && pg_ix < kvm->arch.n_rma_pages) {
pginfo[i].pfn = ri->base_pfn +
(pg_ix << (porder - PAGE_SHIFT));
for (i = 0; i < npages; ++i) {
if (ri && i < ri->npages) {
phys[i] = (ri->base_pfn << PAGE_SHIFT) + (i << porder);
continue;
}
hva = mem->userspace_addr + (i << porder);
Expand All @@ -1183,7 +1179,7 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
hva, compound_order(page));
goto err;
}
pginfo[i].pfn = page_to_pfn(page);
phys[i] = (page_to_pfn(page) << PAGE_SHIFT) | KVMPPC_GOT_PAGE;
}

return 0;
Expand All @@ -1192,6 +1188,28 @@ int kvmppc_core_prepare_memory_region(struct kvm *kvm,
return -EINVAL;
}

static void unpin_slot(struct kvm *kvm, int slot_id)
{
unsigned long *physp;
unsigned long j, npages, pfn;
struct page *page;

physp = kvm->arch.slot_phys[slot_id];
npages = kvm->arch.slot_npages[slot_id];
if (physp) {
for (j = 0; j < npages; j++) {
if (!(physp[j] & KVMPPC_GOT_PAGE))
continue;
pfn = physp[j] >> PAGE_SHIFT;
page = pfn_to_page(pfn);
SetPageDirty(page);
put_page(page);
}
vfree(physp);
kvm->arch.slot_phys[slot_id] = NULL;
}
}

void kvmppc_core_commit_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem)
{
Expand All @@ -1203,8 +1221,6 @@ void kvmppc_core_commit_memory_region(struct kvm *kvm,
int kvmppc_core_init_vm(struct kvm *kvm)
{
long r;
unsigned long npages = 1ul << (MAX_MEM_ORDER - LARGE_PAGE_ORDER);
long err = -ENOMEM;
unsigned long lpcr;

/* Allocate hashed page table */
Expand All @@ -1214,19 +1230,9 @@ int kvmppc_core_init_vm(struct kvm *kvm)

INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables);

kvm->arch.ram_pginfo = kzalloc(npages * sizeof(struct kvmppc_pginfo),
GFP_KERNEL);
if (!kvm->arch.ram_pginfo) {
pr_err("kvmppc_core_init_vm: couldn't alloc %lu bytes\n",
npages * sizeof(struct kvmppc_pginfo));
goto out_free;
}

kvm->arch.ram_npages = 0;
kvm->arch.ram_psize = 1ul << LARGE_PAGE_ORDER;
kvm->arch.ram_porder = LARGE_PAGE_ORDER;
kvm->arch.rma = NULL;
kvm->arch.n_rma_pages = 0;

kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);

Expand All @@ -1249,25 +1255,15 @@ int kvmppc_core_init_vm(struct kvm *kvm)
kvm->arch.lpcr = lpcr;

return 0;

out_free:
kvmppc_free_hpt(kvm);
return err;
}

void kvmppc_core_destroy_vm(struct kvm *kvm)
{
struct kvmppc_pginfo *pginfo;
unsigned long i;

if (kvm->arch.ram_pginfo) {
pginfo = kvm->arch.ram_pginfo;
kvm->arch.ram_pginfo = NULL;
for (i = kvm->arch.n_rma_pages; i < kvm->arch.ram_npages; ++i)
if (pginfo[i].pfn)
put_page(pfn_to_page(pginfo[i].pfn));
kfree(pginfo);
}
for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
unpin_slot(kvm, i);

if (kvm->arch.rma) {
kvm_release_rma(kvm->arch.rma);
kvm->arch.rma = NULL;
Expand Down
41 changes: 37 additions & 4 deletions arch/powerpc/kvm/book3s_hv_rm_mmu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,25 @@
#include <asm/synch.h>
#include <asm/ppc-opcode.h>

/*
* Since this file is built in even if KVM is a module, we need
* a local copy of this function for the case where kvm_main.c is
* modular.
*/
static struct kvm_memory_slot *builtin_gfn_to_memslot(struct kvm *kvm,
gfn_t gfn)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;

slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, slots)
if (gfn >= memslot->base_gfn &&
gfn < memslot->base_gfn + memslot->npages)
return memslot;
return NULL;
}

/* Translate address of a vmalloc'd thing to a linear map address */
static void *real_vmalloc_addr(void *x)
{
Expand Down Expand Up @@ -59,10 +78,12 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
{
unsigned long porder;
struct kvm *kvm = vcpu->kvm;
unsigned long i, lpn, pa;
unsigned long i, gfn, lpn, pa;
unsigned long *hpte;
struct revmap_entry *rev;
unsigned long g_ptel = ptel;
struct kvm_memory_slot *memslot;
unsigned long *physp;

/* only handle 4k, 64k and 16M pages for now */
porder = 12;
Expand All @@ -80,12 +101,24 @@ long kvmppc_h_enter(struct kvm_vcpu *vcpu, unsigned long flags,
} else
return H_PARAMETER;
}
lpn = (ptel & HPTE_R_RPN) >> kvm->arch.ram_porder;
if (lpn >= kvm->arch.ram_npages || porder > kvm->arch.ram_porder)
if (porder > kvm->arch.ram_porder)
return H_PARAMETER;
pa = kvm->arch.ram_pginfo[lpn].pfn << PAGE_SHIFT;

gfn = ((ptel & HPTE_R_RPN) & ~((1ul << porder) - 1)) >> PAGE_SHIFT;
memslot = builtin_gfn_to_memslot(kvm, gfn);
if (!(memslot && !(memslot->flags & KVM_MEMSLOT_INVALID)))
return H_PARAMETER;
physp = kvm->arch.slot_phys[memslot->id];
if (!physp)
return H_PARAMETER;

lpn = (gfn - memslot->base_gfn) >> (kvm->arch.ram_porder - PAGE_SHIFT);
physp = real_vmalloc_addr(physp + lpn);
pa = *physp;
if (!pa)
return H_PARAMETER;
pa &= PAGE_MASK;

/* Check WIMG */
if ((ptel & HPTE_R_WIMG) != HPTE_R_M &&
(ptel & HPTE_R_WIMG) != (HPTE_R_W | HPTE_R_I | HPTE_R_M))
Expand Down

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