[PATCH v3 04/14] KVM: PPC: Keep page physical addresses in per-slot arrays
Alexander Graf
agraf at suse.de
Tue Dec 20 02:10:09 EST 2011
On 12.12.2011, at 23:28, Paul Mackerras wrote:
> 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 at samba.org>
> ---
> arch/powerpc/include/asm/kvm_host.h | 9 ++-
> arch/powerpc/kvm/book3s_64_mmu_hv.c | 18 +++---
> arch/powerpc/kvm/book3s_hv.c | 114 +++++++++++++++++------------------
> arch/powerpc/kvm/book3s_hv_rm_mmu.c | 41 +++++++++++-
> 4 files changed, 107 insertions(+), 75 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 629df2e..7a17ab5 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -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
> @@ -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 */
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index 80ece8d..e4c6069 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -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))
> @@ -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;
> /*
> @@ -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 |
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index da7db14..86d3e4b 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -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 */
> @@ -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)
> @@ -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);
> @@ -1108,12 +1108,11 @@ 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;
> @@ -1125,20 +1124,21 @@ 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;
> @@ -1171,7 +1171,6 @@ 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;
> @@ -1195,12 +1194,9 @@ 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);
> @@ -1216,7 +1212,7 @@ 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;
> @@ -1225,6 +1221,28 @@ 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)
> {
> @@ -1236,8 +1254,6 @@ 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 */
> @@ -1247,19 +1263,9 @@ 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);
>
> @@ -1282,25 +1288,15 @@ 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;
> diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> index 6148493..84dae82 100644
> --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
> @@ -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)
> +{
Shouldn't this rather be in a header file then? I'd rather not have this code duplicated. Please follow up with a patch to merge this copy and the real one into something in a header file.
Alex
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