| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <alpine.DEB.2.02.1208171818260.15568@kaball.uk.xensource.com>
Date: Fri, 17 Aug 2012 18:25:56 +0100
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
Subject: Re: [Xen-devel] [PATCH 4/5] xen/swiotlb: Use the swiotlb_late_init_with_tbl
to init Xen-SWIOTLB late when PV PCI is used.
On Thu, 16 Aug 2012, Konrad Rzeszutek Wilk wrote:
> With this patch we provide the functionality to initialize the
> Xen-SWIOTLB late in the bootup cycle - specifically for
> Xen PCI-frontend. We still will work if the user had
> supplied 'iommu=soft' on the Linux command line.
>
> CC: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
> [v1: Fix smatch warnings]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> ---
> arch/x86/include/asm/xen/swiotlb-xen.h | 2 +
> arch/x86/xen/pci-swiotlb-xen.c | 17 +++++++++-
> drivers/xen/swiotlb-xen.c | 54 ++++++++++++++++++++++++++-----
> include/xen/swiotlb-xen.h | 1 +
> 4 files changed, 64 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
> index 1be1ab7..ee52fca 100644
> --- a/arch/x86/include/asm/xen/swiotlb-xen.h
> +++ b/arch/x86/include/asm/xen/swiotlb-xen.h
> @@ -5,10 +5,12 @@
> extern int xen_swiotlb;
> extern int __init pci_xen_swiotlb_detect(void);
> extern void __init pci_xen_swiotlb_init(void);
> +extern int pci_xen_swiotlb_init_late(void);
> #else
> #define xen_swiotlb (0)
> static inline int __init pci_xen_swiotlb_detect(void) { return 0; }
> static inline void __init pci_xen_swiotlb_init(void) { }
> +static inline int pci_xen_swiotlb_init_late(void) { return -ENXIO; }
> #endif
>
> #endif /* _ASM_X86_SWIOTLB_XEN_H */
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 1c17227..031d8bc 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -12,7 +12,7 @@
> #include <asm/iommu.h>
> #include <asm/dma.h>
> #endif
> -
> +#include <linux/export.h>
> int xen_swiotlb __read_mostly;
>
> static struct dma_map_ops xen_swiotlb_dma_ops = {
> @@ -76,6 +76,21 @@ void __init pci_xen_swiotlb_init(void)
> pci_request_acs();
> }
> }
> +
> +int pci_xen_swiotlb_init_late(void)
> +{
> + int rc = xen_swiotlb_late_init(1);
> + if (rc)
> + return rc;
> +
> + dma_ops = &xen_swiotlb_dma_ops;
> + /* Make sure ACS will be enabled */
> + pci_request_acs();
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
shouldn't we be checking whether the xen_swiotlb has already been
initialized?
> IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
> 0,
> pci_xen_swiotlb_init,
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 1afb4fb..1942a3e 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -145,13 +145,14 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
> return 0;
> }
>
> -void __init xen_swiotlb_init(int verbose)
> +static int __ref __xen_swiotlb_init(int verbose, bool early)
> {
> unsigned long bytes;
> int rc = -ENOMEM;
> unsigned long nr_tbl;
> char *m = NULL;
> unsigned int repeat = 3;
> + unsigned long order;
>
> nr_tbl = swiotlb_nr_tbl();
> if (nr_tbl)
> @@ -161,12 +162,31 @@ void __init xen_swiotlb_init(int verbose)
> xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
> }
> retry:
> + order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
> bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
>
> /*
> * Get IO TLB memory from any location.
> */
> - xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
> + if (early)
> + xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
> + else {
> +#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
> +#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
> + while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
> + xen_io_tlb_start = (void *)__get_free_pages(__GFP_NOWARN, order);
> + if (xen_io_tlb_start)
> + break;
> + order--;
> + }
> + if (order != get_order(bytes)) {
> + pr_warn("Warning: only able to allocate %ld MB "
> + "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
> + xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
> + bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
> + }
> + }
> if (!xen_io_tlb_start) {
> m = "Cannot allocate Xen-SWIOTLB buffer!\n";
> goto error;
> @@ -179,17 +199,22 @@ retry:
> bytes,
> xen_io_tlb_nslabs);
> if (rc) {
> - free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
> + if (early)
> + free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
> m = "Failed to get contiguous memory for DMA from Xen!\n"\
> "You either: don't have the permissions, do not have"\
> " enough free memory under 4GB, or the hypervisor memory"\
> - "is too fragmented!";
> + " is too fragmented!";
> goto error;
> }
> start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
> - swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
>
> - return;
> + rc = 0;
> + if (early)
> + swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs, verbose);
> + else
> + rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
> + return rc;
> error:
> if (repeat--) {
> xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
> @@ -198,10 +223,21 @@ error:
> (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
> goto retry;
> }
> - xen_raw_printk("%s (rc:%d)", m, rc);
> - panic("%s (rc:%d)", m, rc);
> + pr_err("%s (rc:%d)", m, rc);
> + if (early)
> + panic("%s (rc:%d)", m, rc);
> + else
> + free_pages((unsigned long)xen_io_tlb_start, order);
> + return rc;
> +}
All these "if" make the code a harder to read. Would it be possible at
least to unify the error paths and just check on after_bootmem whether
we need to call free_pages or free_bootmem?
In fact using after_bootmem you might get away without an early
parameter.
> +void __init xen_swiotlb_init(int verbose)
> +{
> + __xen_swiotlb_init(verbose, true /* early */);
> +}
> +int xen_swiotlb_late_init(int verbose)
> +{
> + return __xen_swiotlb_init(verbose, false /* late */);
> }
> void *
> xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> dma_addr_t *dma_handle, gfp_t flags,
> diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h
> index 4f4d449..d38d984 100644
> --- a/include/xen/swiotlb-xen.h
> +++ b/include/xen/swiotlb-xen.h
> @@ -4,6 +4,7 @@
> #include <linux/swiotlb.h>
>
> extern void xen_swiotlb_init(int verbose);
> +extern int xen_swiotlb_late_init(int verbose);
>
> extern void
> *xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> --
> 1.7.7.6
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> http://lists.xen.org/xen-devel
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists