Re: [PATCH v2 07/10] PPC, KVM, CMA: use general CMA reserved area management framework

Aneesh Kumar K.V
2014-06-14T10:05:33Z

Joonsoo Kim <iamjoonsoo.kim@lge.com> writes:

> Now, we have general CMA reserved area management framework,
> so use it for future maintainabilty. There is no functional change.
>
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
> index 7cde8a6..28ec226 100644
> --- a/arch/powerpc/kvm/book3s_hv_builtin.c
> +++ b/arch/powerpc/kvm/book3s_hv_builtin.c
> @@ -16,12 +16,14 @@
> #include <linux/init.h>
> #include <linux/memblock.h>
> #include <linux/sizes.h>
> +#include <linux/cma.h>
>
> #include <asm/cputable.h>
> #include <asm/kvm_ppc.h>
> #include <asm/kvm_book3s.h>
>
> -#include "book3s_hv_cma.h"
> +#define KVM_CMA_CHUNK_ORDER 18
> +
> /*
> * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
> * should be power of 2.
> @@ -43,6 +45,8 @@ static unsigned long kvm_cma_resv_ratio = 5;
> unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT; /* 128MB */
> EXPORT_SYMBOL_GPL(kvm_rma_pages);
>
> +static struct cma *kvm_cma;
> +
> /* Work out RMLS (real mode limit selector) field value for a given RMA size.
> Assumes POWER7 or PPC970. */
> static inline int lpcr_rmls(unsigned long rma_size)
> @@ -97,7 +101,7 @@ struct kvm_rma_info *kvm_alloc_rma()
> ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
> if (!ri)
> return NULL;
> - page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
> + page = cma_alloc(kvm_cma, kvm_rma_pages, get_order(kvm_rma_pages));
> if (!page)
> goto err_out;
> atomic_set(&ri->use_count, 1);
> @@ -112,7 +116,7 @@ EXPORT_SYMBOL_GPL(kvm_alloc_rma);
> void kvm_release_rma(struct kvm_rma_info *ri)
> {
> if (atomic_dec_and_test(&ri->use_count)) {
> - kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
> + cma_release(kvm_cma, pfn_to_page(ri->base_pfn), kvm_rma_pages);
> kfree(ri);
> }
> }
> @@ -134,13 +138,13 @@ struct page *kvm_alloc_hpt(unsigned long nr_pages)
> /* Old CPUs require HPT aligned on a multiple of its size */
> if (!cpu_has_feature(CPU_FTR_ARCH_206))
> align_pages = nr_pages;
> - return kvm_alloc_cma(nr_pages, align_pages);
> + return cma_alloc(kvm_cma, nr_pages, get_order(align_pages));
> }
> EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
>
> void kvm_release_hpt(struct page *page, unsigned long nr_pages)
> {
> - kvm_release_cma(page, nr_pages);
> + cma_release(kvm_cma, page, nr_pages);
> }
> EXPORT_SYMBOL_GPL(kvm_release_hpt);
>
> @@ -179,7 +183,8 @@ void __init kvm_cma_reserve(void)
> align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
>
> align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
> - kvm_cma_declare_contiguous(selected_size, align_size);
> + cma_declare_contiguous(selected_size, 0, 0, align_size,
> + KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
> }
> }
>
> diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c
> deleted file mode 100644
> index d9d3d85..0000000
> --- a/arch/powerpc/kvm/book3s_hv_cma.c
> +++ /dev/null
> @@ -1,240 +0,0 @@
> -/*
> - * Contiguous Memory Allocator for ppc KVM hash pagetable based on CMA
> - * for DMA mapping framework
> - *
> - * Copyright IBM Corporation, 2013
> - * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> - *
> - * This program is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU General Public License as
> - * published by the Free Software Foundation; either version 2 of the
> - * License or (at your optional) any later version of the license.
> - *
> - */
> -#define pr_fmt(fmt) "kvm_cma: " fmt
> -
> -#ifdef CONFIG_CMA_DEBUG
> -#ifndef DEBUG
> -# define DEBUG
> -#endif
> -#endif
> -
> -#include <linux/memblock.h>
> -#include <linux/mutex.h>
> -#include <linux/sizes.h>
> -#include <linux/slab.h>
> -
> -#include "book3s_hv_cma.h"
> -
> -struct kvm_cma {
> - unsigned long base_pfn;
> - unsigned long count;
> - unsigned long *bitmap;
> -};
> -
> -static DEFINE_MUTEX(kvm_cma_mutex);
> -static struct kvm_cma kvm_cma_area;
> -
> -/**
> - * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling
> - * for kvm hash pagetable
> - * @size: Size of the reserved memory.
> - * @alignment: Alignment for the contiguous memory area
> - *
> - * This function reserves memory for kvm cma area. It should be
> - * called by arch code when early allocator (memblock or bootmem)
> - * is still activate.
> - */
> -long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment)
> -{
> - long base_pfn;
> - phys_addr_t addr;
> - struct kvm_cma *cma = &kvm_cma_area;
> -
> - pr_debug("%s(size %lx)\n", __func__, (unsigned long)size);
> -
> - if (!size)
> - return -EINVAL;
> - /*
> - * Sanitise input arguments.
> - * We should be pageblock aligned for CMA.
> - */
> - alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order));
> - size = ALIGN(size, alignment);
> - /*
> - * Reserve memory
> - * Use __memblock_alloc_base() since
> - * memblock_alloc_base() panic()s.
> - */
> - addr = __memblock_alloc_base(size, alignment, 0);
> - if (!addr) {
> - base_pfn = -ENOMEM;
> - goto err;
> - } else
> - base_pfn = PFN_DOWN(addr);
> -
> - /*
> - * Each reserved area must be initialised later, when more kernel
> - * subsystems (like slab allocator) are available.
> - */
> - cma->base_pfn = base_pfn;
> - cma->count = size >> PAGE_SHIFT;
> - pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M);
> - return 0;
> -err:
> - pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> - return base_pfn;
> -}
> -
> -/**
> - * kvm_alloc_cma() - allocate pages from contiguous area
> - * @nr_pages: Requested number of pages.
> - * @align_pages: Requested alignment in number of pages
> - *
> - * This function allocates memory buffer for hash pagetable.
> - */
> -struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages)
> -{
> - int ret;
> - struct page *page = NULL;
> - struct kvm_cma *cma = &kvm_cma_area;
> - unsigned long chunk_count, nr_chunk;
> - unsigned long mask, pfn, pageno, start = 0;
> -
> -
> - if (!cma || !cma->count)
> - return NULL;
> -
> - pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__,
> - (void *)cma, nr_pages, align_pages);
> -
> - if (!nr_pages)
> - return NULL;
> - /*
> - * align mask with chunk size. The bit tracks pages in chunk size
> - */
> - VM_BUG_ON(!is_power_of_2(align_pages));
> - mask = (align_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT)) - 1;
> - BUILD_BUG_ON(PAGE_SHIFT > KVM_CMA_CHUNK_ORDER);
> -
> - chunk_count = cma->count >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
> - nr_chunk = nr_pages >> (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT);
> -
> - mutex_lock(&kvm_cma_mutex);
> - for (;;) {
> - pageno = bitmap_find_next_zero_area(cma->bitmap, chunk_count,
> - start, nr_chunk, mask);
> - if (pageno >= chunk_count)
> - break;
> -
> - pfn = cma->base_pfn + (pageno << (KVM_CMA_CHUNK_ORDER - PAGE_SHIFT));
> - ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA);
> - if (ret == 0) {
> - bitmap_set(cma->bitmap, pageno, nr_chunk);
> - page = pfn_to_page(pfn);
> - memset(pfn_to_kaddr(pfn), 0, nr_pages <<
> PAGE_SHIFT);

The above memset is missing in the generic code. May be

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 6f13ee6..8740b4c 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -75,6 +75,7 @@ long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
page = kvm_alloc_hpt(1 << (order - PAGE_SHIFT));
if (page) {
hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
+ memset((void *)hpt, 0, (1 << order));
kvm->arch.hpt_cma_alloc = 1;
} else
--order;

With that

Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

-aneesh