Re: [PATCH v2 8/9] io/x86: Factor out ioremap()

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On Wed, Apr 27, 2016 at 03:13:57PM +0200, Alexander Gordeev wrote:
> Cc: Andrew Jones <drjones@xxxxxxxxxx>
> Cc: Thomas Huth <thuth@xxxxxxxxxx>
> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
> ---
>  lib/x86/asm/io.h |  3 +++
>  lib/x86/io.c     | 14 ++++++++++++++
>  x86/vmexit.c     | 10 ++--------
>  3 files changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/x86/asm/io.h b/lib/x86/asm/io.h
> index c37450f..d8c5dbd 100644
> --- a/lib/x86/asm/io.h
> +++ b/lib/x86/asm/io.h
> @@ -42,6 +42,9 @@ static inline void outl(unsigned int value, unsigned short port)
>      asm volatile("outl %0, %w1" : : "a"(value), "Nd"(port));
>  }
>  
> +#define ioremap ioremap
> +void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
> +
>  #include <asm-generic/io.h>
>  
>  #endif
> diff --git a/lib/x86/io.c b/lib/x86/io.c
> index d396d42..a699509 100644
> --- a/lib/x86/io.c
> +++ b/lib/x86/io.c
> @@ -1,4 +1,5 @@
>  #include "libcflat.h"
> +#include "vm.h"
>  #include "smp.h"
>  #include "asm/io.h"
>  #ifndef USE_SERIAL
> @@ -81,3 +82,16 @@ void exit(int code)
>          asm volatile("out %0, %1" : : "a"(code), "d"((short)0xf4));
>  #endif
>  }
> +
> +void __iomem *ioremap(phys_addr_t phys_addr, size_t size)
> +{
> +	phys_addr_t base = ALIGN(phys_addr, PAGE_SIZE);

ALIGN() aligns up, so base will be larger than phys_addr, and then...

> +	phys_addr_t off = phys_addr - base;

...here off is going to be some massive number. But then...

> +	ulong nr = ALIGN(off + size + (PAGE_SIZE - 1), PAGE_SIZE) / PAGE_SIZE;

...it probably gets small again here after adding size (PAGE_SIZE called
from vmexit.c) and PAGE_SIZE-1. So you probably end up with nr=1 anyway.

Also, since ALIGN() aligns up, you don't need the '+ (PAGE_SIZE - 1)'
here.

> +	void *page = alloc_vpages(nr);
> +
> +	install_page((void *)read_cr3(), base, page);
> +
> +	return page + off;
> +}
> +
> diff --git a/x86/vmexit.c b/x86/vmexit.c
> index db7dbd8..c2e1e49 100644
> --- a/x86/vmexit.c
> +++ b/x86/vmexit.c
> @@ -371,8 +371,7 @@ int main(int ac, char **av)
>  {
>  	struct fadt_descriptor_rev1 *fadt;
>  	int i;
> -	unsigned long membar = 0, base, offset;
> -	void *m;
> +	unsigned long membar = 0;
>  	pcidevaddr_t pcidev;
>  
>  	smp_init();
> @@ -394,12 +393,7 @@ int main(int ac, char **av)
>  			}
>  			if (pci_bar_is_memory(pcidev, i)) {
>  				membar = pci_bar_addr(pcidev, i);
> -				base = membar & ~4095;
> -				offset = membar - base;
> -				m = alloc_vpages(1);
> -				
> -				install_page((void *)read_cr3(), base, m);
> -				pci_test.memaddr = m + offset;
> +				pci_test.memaddr = ioremap(membar, PAGE_SIZE);
>  			} else {
>  				pci_test.iobar = pci_bar_addr(pcidev, i);
>  			}
> -- 
> 1.8.3.1
>

Thanks,
drew 
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