From: "Jan Beulich" <JBeulich@suse.com>
To: "David Vrabel" <david.vrabel@citrix.com>
Cc: <x86@kernel.org>, "Thomas Gleixner" <tglx@linutronix.de>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
<xen-devel@lists.xenproject.org>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Ingo Molnar" <mingo@redhat.com>, <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [Xen-devel] [PATCH 3/3] x86/xen: use the maximum MFN to calculate the required DMA mask
Date: Wed, 12 Nov 2014 15:55:24 +0000 [thread overview]
Message-ID: <546390FC0200007800046E50@mail.emea.novell.com> (raw)
In-Reply-To: <1415805906-27316-4-git-send-email-david.vrabel@citrix.com>
>>> On 12.11.14 at 16:25, <david.vrabel@citrix.com> wrote:
> +u64
> +xen_swiotlb_get_required_mask(struct device *dev)
> +{
> + u64 max_mfn;
> +
> + max_mfn = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
> +
> + return DMA_BIT_MASK(fls64(max_mfn << PAGE_SHIFT) + 1);
> +}
The value the hypercall returns is exclusive and an unsigned long.
Hence I'd suggest
u64
xen_swiotlb_get_required_mask(struct device *dev)
{
unsigned long max_mfn;
max_mfn = HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL);
return DMA_BIT_MASK(__fls(max_mfn - 1) + 1 + PAGE_SHIFT);
}
Jan
next prev parent reply other threads:[~2014-11-12 15:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-12 15:25 [PATCHv2 0/3]: dma,x86,xen: reduce SWIOTLB usage in Xen guests David Vrabel
2014-11-12 15:25 ` [PATCH 1/3] dma,ia64: add dma_get_required_mask_from_max_pfn() David Vrabel
2014-11-14 15:11 ` [Xen-devel] [PATCH 1/3] dma, ia64: " Stefano Stabellini
2014-11-12 15:25 ` [PATCH 2/3] x86: allow dma_get_required_mask() to be overridden David Vrabel
2014-11-13 10:25 ` [Xen-devel] " Jan Beulich
2014-11-13 10:30 ` David Vrabel
2014-11-13 10:32 ` Jan Beulich
2014-11-14 15:19 ` Stefano Stabellini
2014-11-12 15:25 ` [PATCH 3/3] x86/xen: use the maximum MFN to calculate the required DMA mask David Vrabel
2014-11-12 15:55 ` Jan Beulich [this message]
2014-11-12 16:59 ` [Xen-devel] " David Vrabel
2014-11-12 17:18 ` Jan Beulich
2014-11-13 9:57 ` Jan Beulich
2014-11-13 10:38 ` Andrew Cooper
2014-11-13 10:53 ` Jan Beulich
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