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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v9 2/3] tools/libxc: add API for bitmap access for restore
On 01/09/17 17:08, Olaf Hering wrote:
> Extend API for managing bitmaps. Each bitmap is now represented by a
> generic struct xc_sr_bitmap.
> Switch the existing populated_pfns to this API.
>
> Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
> Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> ---
> tools/libxc/xc_sr_common.c | 41 ++++++++++++++++++++++++++
> tools/libxc/xc_sr_common.h | 72
> +++++++++++++++++++++++++++++++++++++++++++--
> tools/libxc/xc_sr_restore.c | 66 ++---------------------------------------
> 3 files changed, 114 insertions(+), 65 deletions(-)
>
> diff --git a/tools/libxc/xc_sr_common.c b/tools/libxc/xc_sr_common.c
> index 79b9c3e940..4d221ca90c 100644
> --- a/tools/libxc/xc_sr_common.c
> +++ b/tools/libxc/xc_sr_common.c
> @@ -155,6 +155,47 @@ static void __attribute__((unused))
> build_assertions(void)
> BUILD_BUG_ON(sizeof(struct xc_sr_rec_hvm_params) != 8);
> }
>
> +/*
> + * Expand the tracking structures as needed.
> + * To avoid realloc()ing too excessively, the size increased to the nearest
> power
> + * of two large enough to contain the required number of bits.
> + */
> +bool _xc_sr_bitmap_resize(struct xc_sr_bitmap *bm, unsigned long bits)
> +{
> + if (bits > bm->bits)
Libxc uses the hypervisor coding style, and xc_sr_* currently have a
consistent style.
> + {
> + size_t new_max;
> + size_t old_sz, new_sz;
> + void *p;
> +
> + /* Round up to the nearest power of two larger than bit, less 1. */
> + new_max = bits;
> + new_max |= new_max >> 1;
> + new_max |= new_max >> 2;
> + new_max |= new_max >> 4;
> + new_max |= new_max >> 8;
> + new_max |= new_max >> 16;
> +#ifdef __x86_64__
> + new_max |= new_max >> 32;
> +#endif
> +
> + old_sz = bitmap_size(bm->bits + 1);
> + new_sz = bitmap_size(new_max + 1);
> + p = realloc(bm->p, new_sz);
> + if (!p)
> + return false;
> +
> + if (bm->p)
> + memset(p + old_sz, 0, new_sz - old_sz);
> + else
> + memset(p, 0, new_sz);
> +
> + bm->p = p;
> + bm->bits = new_max;
> + }
> + return true;
> +}
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/tools/libxc/xc_sr_common.h b/tools/libxc/xc_sr_common.h
> index a83f22af4e..734320947a 100644
> --- a/tools/libxc/xc_sr_common.h
> +++ b/tools/libxc/xc_sr_common.h
> @@ -172,6 +172,12 @@ struct xc_sr_x86_pv_restore_vcpu
> size_t basicsz, extdsz, xsavesz, msrsz;
> };
>
> +struct xc_sr_bitmap
> +{
> + void *p;
> + unsigned long bits;
> +};
> +
> struct xc_sr_context
> {
> xc_interface *xch;
> @@ -255,8 +261,7 @@ struct xc_sr_context
> domid_t xenstore_domid, console_domid;
>
> /* Bitmap of currently populated PFNs during restore. */
> - unsigned long *populated_pfns;
> - xen_pfn_t max_populated_pfn;
> + struct xc_sr_bitmap populated_pfns;
>
> /* Sender has invoked verify mode on the stream. */
> bool verify;
> @@ -343,6 +348,69 @@ extern struct xc_sr_save_ops save_ops_x86_hvm;
> extern struct xc_sr_restore_ops restore_ops_x86_pv;
> extern struct xc_sr_restore_ops restore_ops_x86_hvm;
>
> +extern bool _xc_sr_bitmap_resize(struct xc_sr_bitmap *bm, unsigned long
> bits);
No need for extern on function prototypes.
> +
> +static inline bool xc_sr_bitmap_resize(struct xc_sr_bitmap *bm, unsigned
> long bits)
> +{
> + if (bits > bm->bits)
> + return _xc_sr_bitmap_resize(bm, bits);
> + return true;
> +}
> +
> +static inline void xc_sr_bitmap_free(struct xc_sr_bitmap *bm)
> +{
> + free(bm->p);
> + bm->p = NULL;
bm->bits = 0, or a subsequent test/set/clear will fall over a NULL pointer.
> +}
> +
> +static inline bool xc_sr_set_bit(unsigned long bit, struct xc_sr_bitmap *bm)
> +{
> + if (!xc_sr_bitmap_resize(bm, bit))
There's a boundary condition here trying to test bit 0 of an empty bitmap.
> + return false;
> +
> + set_bit(bit, bm->p);
> + return true;
> +}
> +
> +static inline bool xc_sr_test_bit(unsigned long bit, struct xc_sr_bitmap *bm)
> +{
> + if (bit > bm->bits)
> + return false;
> + return !!test_bit(bit, bm->p);
> +}
> +
> +static inline bool xc_sr_test_and_clear_bit(unsigned long bit, struct
> xc_sr_bitmap *bm)
> +{
> + if (bit > bm->bits)
> + return false;
> + return !!test_and_clear_bit(bit, bm->p);
> +}
> +
> +static inline bool xc_sr_test_and_set_bit(unsigned long bit, struct
> xc_sr_bitmap *bm)
> +{
> + if (bit > bm->bits)
> + return false;
> + return !!test_and_set_bit(bit, bm->p);
> +}
> +
> +static inline bool pfn_is_populated(struct xc_sr_context *ctx, xen_pfn_t pfn)
> +{
> + return xc_sr_test_bit(pfn, &ctx->restore.populated_pfns);
> +}
> +
> +static inline int pfn_set_populated(struct xc_sr_context *ctx, xen_pfn_t pfn)
> +{
> + xc_interface *xch = ctx->xch;
> +
> + if ( !xc_sr_set_bit(pfn, &ctx->restore.populated_pfns) )
> + {
> + ERROR("Failed to realloc populated_pfns bitmap");
> + errno = ENOMEM;
> + return -1;
> + }
> + return 0;
> +}
Why are these moved? They are still restore specific.
~Andrew
> +
> struct xc_sr_record
> {
> uint32_t type;
> diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
> index a016678332..d53948e1a6 100644
> --- a/tools/libxc/xc_sr_restore.c
> +++ b/tools/libxc/xc_sr_restore.c
> @@ -68,64 +68,6 @@ static int read_headers(struct xc_sr_context *ctx)
> return 0;
> }
>
> -/*
> - * Is a pfn populated?
> - */
> -static bool pfn_is_populated(const struct xc_sr_context *ctx, xen_pfn_t pfn)
> -{
> - if ( pfn > ctx->restore.max_populated_pfn )
> - return false;
> - return test_bit(pfn, ctx->restore.populated_pfns);
> -}
> -
> -/*
> - * Set a pfn as populated, expanding the tracking structures if needed. To
> - * avoid realloc()ing too excessively, the size increased to the nearest
> power
> - * of two large enough to contain the required pfn.
> - */
> -static int pfn_set_populated(struct xc_sr_context *ctx, xen_pfn_t pfn)
> -{
> - xc_interface *xch = ctx->xch;
> -
> - if ( pfn > ctx->restore.max_populated_pfn )
> - {
> - xen_pfn_t new_max;
> - size_t old_sz, new_sz;
> - unsigned long *p;
> -
> - /* Round up to the nearest power of two larger than pfn, less 1. */
> - new_max = pfn;
> - new_max |= new_max >> 1;
> - new_max |= new_max >> 2;
> - new_max |= new_max >> 4;
> - new_max |= new_max >> 8;
> - new_max |= new_max >> 16;
> -#ifdef __x86_64__
> - new_max |= new_max >> 32;
> -#endif
> -
> - old_sz = bitmap_size(ctx->restore.max_populated_pfn + 1);
> - new_sz = bitmap_size(new_max + 1);
> - p = realloc(ctx->restore.populated_pfns, new_sz);
> - if ( !p )
> - {
> - ERROR("Failed to realloc populated bitmap");
> - errno = ENOMEM;
> - return -1;
> - }
> -
> - memset((uint8_t *)p + old_sz, 0x00, new_sz - old_sz);
> -
> - ctx->restore.populated_pfns = p;
> - ctx->restore.max_populated_pfn = new_max;
> - }
> -
> - assert(!test_bit(pfn, ctx->restore.populated_pfns));
> - set_bit(pfn, ctx->restore.populated_pfns);
> -
> - return 0;
> -}
> -
> /*
> * Given a set of pfns, obtain memory from Xen to fill the physmap for the
> * unpopulated subset. If types is NULL, no page type checking is performed
> @@ -684,10 +626,8 @@ static int setup(struct xc_sr_context *ctx)
> if ( rc )
> goto err;
>
> - ctx->restore.max_populated_pfn = (32 * 1024 / 4) - 1;
> - ctx->restore.populated_pfns = bitmap_alloc(
> - ctx->restore.max_populated_pfn + 1);
> - if ( !ctx->restore.populated_pfns )
> + rc = !xc_sr_bitmap_resize(&ctx->restore.populated_pfns, 32 * 1024 / 4);
> + if ( rc )
> {
> ERROR("Unable to allocate memory for populated_pfns bitmap");
> rc = -1;
> @@ -722,7 +662,7 @@ static void cleanup(struct xc_sr_context *ctx)
> xc_hypercall_buffer_free_pages(xch, dirty_bitmap,
>
> NRPAGES(bitmap_size(ctx->restore.p2m_size)));
> free(ctx->restore.buffered_records);
> - free(ctx->restore.populated_pfns);
> + xc_sr_bitmap_free(&ctx->restore.populated_pfns);
> if ( ctx->restore.ops.cleanup(ctx) )
> PERROR("Failed to clean up");
> }
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