Re: [PATCH 06/11] x86/dma: Get rid of iommu_pass_through

Borislav Petkov
2019-08-20T11:17:53Z

On Mon, Aug 19, 2019 at 03:22:51PM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
>
> This variable has no users anymore. Remove it and tell the
> IOMMU code via its new functions about requested DMA modes.
>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
> arch/x86/include/asm/iommu.h | 1 -
> arch/x86/kernel/pci-dma.c | 20 +++-----------------
> 2 files changed, 3 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
> index baedab8ac538..b91623d521d9 100644
> --- a/arch/x86/include/asm/iommu.h
> +++ b/arch/x86/include/asm/iommu.h
> @@ -4,7 +4,6 @@
>
> extern int force_iommu, no_iommu;
> extern int iommu_detected;
> -extern int iommu_pass_through;
>
> /* 10 seconds */
> #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index f62b498b18fb..fa4352dce491 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <linux/dma-direct.h>
> #include <linux/dma-debug.h>
> +#include <linux/iommu.h>
> #include <linux/dmar.h>
> #include <linux/export.h>
> #include <linux/memblock.h>
> @@ -34,21 +35,6 @@ int no_iommu __read_mostly;
> /* Set this to 1 if there is a HW IOMMU in the system */
> int iommu_detected __read_mostly = 0;
>
> -/*
> - * This variable becomes 1 if iommu=pt is passed on the kernel command line.
> - * If this variable is 1, IOMMU implementations do no DMA translation for
> - * devices and allow every device to access to whole physical memory. This is
> - * useful if a user wants to use an IOMMU only for KVM device assignment to
> - * guests and not for driver dma translation.
> - * It is also possible to disable by default in kernel config, and enable with
> - * iommu=nopt at boot time.
> - */
> -#ifdef CONFIG_IOMMU_DEFAULT_PASSTHROUGH
> -int iommu_pass_through __read_mostly = 1;
> -#else
> -int iommu_pass_through __read_mostly;
> -#endif
> -
> extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
>
> void __init pci_iommu_alloc(void)
> @@ -120,9 +106,9 @@ static __init int iommu_setup(char *p)
> swiotlb = 1;
> #endif
> if (!strncmp(p, "pt", 2))
> - iommu_pass_through = 1;
> + iommu_set_default_passthrough(true);
> if (!strncmp(p, "nopt", 4))
> - iommu_pass_through = 0;
> + iommu_set_default_translated(true);
>
> gart_parse_options(p);
>
> --

Reviewed-by: Borislav Petkov <bp@suse.de>

--
Regards/Gruss,
Boris.

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