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Message-ID: <alpine.DEB.2.02.1401031644120.8667@kaball.uk.xensource.com>
Date: Fri, 3 Jan 2014 16:53:59 +0000
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: <linux-kernel@...r.kernel.org>, <xen-devel@...ts.xenproject.org>,
<boris.ostrovsky@...cle.com>, <david.vrabel@...rix.com>,
<stefano.stabellini@...citrix.com>, <mukesh.rathor@...cle.com>
Subject: Re: [PATCH v12 14/18] xen/grant: Implement an grant frame array
struct.
On Tue, 31 Dec 2013, Konrad Rzeszutek Wilk wrote:
> The 'xen_hvm_resume_frames' used to be an 'unsigned long'
> and contain the virtual address of the grants. That was OK
> for most architectures (PVHVM, ARM) were the grants are contingous
> in memory. That however is not the case for PVH - in which case
> we will have to do a lookup for each virtual address for the PFN.
>
> Instead of doing that, lets make it a structure which will contain
> the array of PFNs, the virtual address and the count of said PFNs.
>
> Also provide a generic functions: gnttab_setup_auto_xlat_frames and
> gnttab_free_auto_xlat_frames to populate said structure with
> appropiate values for PVHVM and ARM.
^appropriate
> To round it off, change the name from 'xen_hvm_resume_frames' to
> a more descriptive one - 'xen_auto_xlat_grant_frames'.
>
> For PVH, in patch "xen/pvh: Piggyback on PVHVM for grant driver"
> we will populate the 'xen_auto_xlat_grant_frames' by ourselves.
>
> Suggested-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> ---
> arch/arm/xen/enlighten.c | 9 +++++++--
> drivers/xen/grant-table.c | 45 ++++++++++++++++++++++++++++++++++++++++-----
> drivers/xen/platform-pci.c | 10 +++++++---
> include/xen/grant_table.h | 9 ++++++++-
> 4 files changed, 62 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 8550123..2162172 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -208,6 +208,7 @@ static int __init xen_guest_init(void)
> const char *version = NULL;
> const char *xen_prefix = "xen,xen-";
> struct resource res;
> + unsigned long grant_frames;
>
> node = of_find_compatible_node(NULL, NULL, "xen,xen");
> if (!node) {
> @@ -224,10 +225,10 @@ static int __init xen_guest_init(void)
> }
> if (of_address_to_resource(node, GRANT_TABLE_PHYSADDR, &res))
> return 0;
> - xen_hvm_resume_frames = res.start;
> + grant_frames = res.start;
> xen_events_irq = irq_of_parse_and_map(node, 0);
> pr_info("Xen %s support found, events_irq=%d gnttab_frame_pfn=%lx\n",
> - version, xen_events_irq, (xen_hvm_resume_frames >> PAGE_SHIFT));
> + version, xen_events_irq, (grant_frames >> PAGE_SHIFT));
> xen_domain_type = XEN_HVM_DOMAIN;
>
> xen_setup_features();
> @@ -265,6 +266,10 @@ static int __init xen_guest_init(void)
> if (xen_vcpu_info == NULL)
> return -ENOMEM;
>
> + if (gnttab_setup_auto_xlat_frames(grant_frames)) {
> + free_percpu(xen_vcpu_info);
> + return -ENOMEM;
> + }
> gnttab_init();
> if (!xen_initial_domain())
> xenbus_probe(NULL);
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index cc1b4fa..b117fd6 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -65,8 +65,8 @@ static unsigned int nr_grant_frames;
> static int gnttab_free_count;
> static grant_ref_t gnttab_free_head;
> static DEFINE_SPINLOCK(gnttab_list_lock);
> -unsigned long xen_hvm_resume_frames;
> -EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
> +struct grant_frames xen_auto_xlat_grant_frames;
> +EXPORT_SYMBOL_GPL(xen_auto_xlat_grant_frames);
it should be static now
> static union {
> struct grant_entry_v1 *v1;
> @@ -838,6 +838,40 @@ unsigned int gnttab_max_grant_frames(void)
> }
> EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
>
> +int gnttab_setup_auto_xlat_frames(unsigned long addr)
> +{
> + xen_pfn_t *pfn;
> + unsigned int max_nr_gframes = __max_nr_grant_frames();
> + int i;
> +
> + if (xen_auto_xlat_grant_frames.count)
> + return -EINVAL;
> +
> + pfn = kcalloc(max_nr_gframes, sizeof(pfn[0]), GFP_KERNEL);
> + if (!pfn)
> + return -ENOMEM;
> + for (i = 0; i < max_nr_gframes; i++)
> + pfn[i] = PFN_DOWN(addr + (i * PAGE_SIZE));
> +
> + xen_auto_xlat_grant_frames.vaddr = addr;
> + xen_auto_xlat_grant_frames.pfn = pfn;
> + xen_auto_xlat_grant_frames.count = max_nr_gframes;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(gnttab_setup_auto_xlat_frames);
> +
> +void gnttab_free_auto_xlat_frames(void)
> +{
> + if (!xen_auto_xlat_grant_frames.count)
> + return;
> + kfree(xen_auto_xlat_grant_frames.pfn);
> + xen_auto_xlat_grant_frames.pfn = NULL;
> + xen_auto_xlat_grant_frames.count = 0;
> + xen_auto_xlat_grant_frames.vaddr = 0;
> +}
> +EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);
I would leave vaddr alone in gnttab_setup_auto_xlat_frames and
gnttab_free_auto_xlat_frames
> /* Handling of paged out grant targets (GNTST_eagain) */
> #define MAX_DELAY 256
> static inline void
> @@ -1068,6 +1102,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
> struct xen_add_to_physmap xatp;
> unsigned int i = end_idx;
> rc = 0;
> + BUG_ON(xen_auto_xlat_grant_frames.count < nr_gframes);
> /*
> * Loop backwards, so that the first hypercall has the largest
> * index, ensuring that the table will grow only once.
> @@ -1076,7 +1111,7 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
> xatp.domid = DOMID_SELF;
> xatp.idx = i;
> xatp.space = XENMAPSPACE_grant_table;
> - xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
> + xatp.gpfn = xen_auto_xlat_grant_frames.pfn[i];
> rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
> if (rc != 0) {
> pr_warn("grant table add_to_physmap failed, err=%d\n",
> @@ -1175,11 +1210,11 @@ static int gnttab_setup(void)
>
> if (xen_feature(XENFEAT_auto_translated_physmap) && gnttab_shared.addr == NULL)
> {
> - gnttab_shared.addr = xen_remap(xen_hvm_resume_frames,
> + gnttab_shared.addr = xen_remap(xen_auto_xlat_grant_frames.vaddr,
> PAGE_SIZE * max_nr_gframes);
here you can xen_remap xen_auto_xlat_grant_frames.pfn[0] instead
> if (gnttab_shared.addr == NULL) {
> pr_warn("Failed to ioremap gnttab share frames (addr=0x%08lx)!\n",
> - xen_hvm_resume_frames);
> + xen_auto_xlat_grant_frames.vaddr);
> return -ENOMEM;
> }
> }
> diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
> index 2f3528e..f1947ac 100644
> --- a/drivers/xen/platform-pci.c
> +++ b/drivers/xen/platform-pci.c
> @@ -108,6 +108,7 @@ static int platform_pci_init(struct pci_dev *pdev,
> long ioaddr;
> long mmio_addr, mmio_len;
> unsigned int max_nr_gframes;
> + unsigned long grant_frames;
>
> if (!xen_domain())
> return -ENODEV;
> @@ -154,13 +155,16 @@ static int platform_pci_init(struct pci_dev *pdev,
> }
>
> max_nr_gframes = gnttab_max_grant_frames();
> - xen_hvm_resume_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
> + grant_frames = alloc_xen_mmio(PAGE_SIZE * max_nr_gframes);
> + if (gnttab_setup_auto_xlat_frames(grant_frames))
> + goto out;
> ret = gnttab_init();
> if (ret)
> - goto out;
> + goto grant_out;
> xenbus_probe(NULL);
> return 0;
> -
> +grant_out:
> + gnttab_free_auto_xlat_frames();
> out:
> pci_release_region(pdev, 0);
> mem_out:
> diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
> index 694dcaf..a997406 100644
> --- a/include/xen/grant_table.h
> +++ b/include/xen/grant_table.h
> @@ -178,8 +178,15 @@ int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
> grant_status_t **__shared);
> void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
>
> -extern unsigned long xen_hvm_resume_frames;
> +struct grant_frames {
> + xen_pfn_t *pfn;
> + int count;
> + unsigned long vaddr;
> +};
> +extern struct grant_frames xen_auto_xlat_grant_frames;
> unsigned int gnttab_max_grant_frames(void);
> +int gnttab_setup_auto_xlat_frames(unsigned long addr);
> +void gnttab_free_auto_xlat_frames(void);
>
> #define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
>
> --
> 1.8.3.1
>
--
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