Re: [RFC PATCH v4 25/28] x86: Access the setup data through sysfs decrypted

[Tom Lendacky]

On 3/8/2017 1:09 AM, Dave Young wrote:
> On 02/16/17 at 09:47am, Tom Lendacky wrote:
> > Use memremap() to map the setup data.  This will make the appropriate
> > decision as to whether a RAM remapping can be done or if a fallback to
> > ioremap_cache() is needed (similar to the setup data debugfs support).
> >
> > Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> > ---
> >  arch/x86/kernel/ksysfs.c |   27 ++++++++++++++-------------
> >  1 file changed, 14 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/x86/kernel/ksysfs.c b/arch/x86/kernel/ksysfs.c
> > index 4afc67f..d653b3e 100644
> > --- a/arch/x86/kernel/ksysfs.c
> > +++ b/arch/x86/kernel/ksysfs.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/stat.h>
> >  #include <linux/slab.h>
> >  #include <linux/mm.h>
> > +#include <linux/io.h>
> >
> >  #include <asm/io.h>
> >  #include <asm/setup.h>
> > @@ -79,12 +80,12 @@ static int get_setup_data_paddr(int nr, u64 *paddr)
> >  			*paddr = pa_data;
> >  			return 0;
> >  		}
> > -		data = ioremap_cache(pa_data, sizeof(*data));
> > +		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
> >  		if (!data)
> >  			return -ENOMEM;
> >
> >  		pa_data = data->next;
> > -		iounmap(data);
> > +		memunmap(data);
> >  		i++;
> >  	}
> >  	return -EINVAL;
> > @@ -97,17 +98,17 @@ static int __init get_setup_data_size(int nr, size_t *size)
> >  	u64 pa_data = boot_params.hdr.setup_data;
> >
> >  	while (pa_data) {
> > -		data = ioremap_cache(pa_data, sizeof(*data));
> > +		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
> >  		if (!data)
> >  			return -ENOMEM;
> >  		if (nr == i) {
> >  			*size = data->len;
> > -			iounmap(data);
> > +			memunmap(data);
> >  			return 0;
> >  		}
> >
> >  		pa_data = data->next;
> > -		iounmap(data);
> > +		memunmap(data);
> >  		i++;
> >  	}
> >  	return -EINVAL;
> > @@ -127,12 +128,12 @@ static ssize_t type_show(struct kobject *kobj,
> >  	ret = get_setup_data_paddr(nr, &paddr);
> >  	if (ret)
> >  		return ret;
> > -	data = ioremap_cache(paddr, sizeof(*data));
> > +	data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
> >  	if (!data)
> >  		return -ENOMEM;
> >
> >  	ret = sprintf(buf, "0x%x\n", data->type);
> > -	iounmap(data);
> > +	memunmap(data);
> >  	return ret;
> >  }
> >
> > @@ -154,7 +155,7 @@ static ssize_t setup_data_data_read(struct file *fp,
> >  	ret = get_setup_data_paddr(nr, &paddr);
> >  	if (ret)
> >  		return ret;
> > -	data = ioremap_cache(paddr, sizeof(*data));
> > +	data = memremap(paddr, sizeof(*data), MEMREMAP_WB);
> >  	if (!data)
> >  		return -ENOMEM;
> >
> > @@ -170,15 +171,15 @@ static ssize_t setup_data_data_read(struct file *fp,
> >  		goto out;
> >
> >  	ret = count;
> > -	p = ioremap_cache(paddr + sizeof(*data), data->len);
> > +	p = memremap(paddr + sizeof(*data), data->len, MEMREMAP_WB);
> >  	if (!p) {
> >  		ret = -ENOMEM;
> >  		goto out;
> >  	}
> >  	memcpy(buf, p + off, count);
> > -	iounmap(p);
> > +	memunmap(p);
> >  out:
> > -	iounmap(data);
> > +	memunmap(data);
> >  	return ret;
> >  }
> >
> > @@ -250,13 +251,13 @@ static int __init get_setup_data_total_num(u64 pa_data, int *nr)
> >  	*nr = 0;
> >  	while (pa_data) {
> >  		*nr += 1;
> > -		data = ioremap_cache(pa_data, sizeof(*data));
> > +		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
> >  		if (!data) {
> >  			ret = -ENOMEM;
> >  			goto out;
> >  		}
> >  		pa_data = data->next;
> > -		iounmap(data);
> > +		memunmap(data);
> >  	}
> >
> >  out:
>
> It would be better that these cleanup patches are sent separately.

Bjorn suggested something along the same line so I've combined all the
changes from ioremap to memremap as a single pre-patch in the series.
I could send them separately if needed.

Thanks,
Tom

> Acked-by: Dave Young <dyoung@xxxxxxxxxx>
>
> Thanks
> Dave