[PATCH] efi: capsule: allocate whole capsule into virtual memory

[PATCH] efi: capsule: allocate whole capsule into virtual memory

[Austin Christ]

According to UEFI 2.6 section 7.5.3, the capsule should be in contiguous
virtual memory and firmware may consume the capsule immediately. To
correctly implement this functionality, the kernel driver needs to vmap
the entire capsule at the time it is made available to firmware.

The virtual allocation of the capsule update has been changed from kmap,
which was only allocating the first page of the update, to vmap and
allocates the entire data payload.

Signed-off-by: Austin Christ <austinwc@codeaurora.org>
---
 drivers/firmware/efi/capsule-loader.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
index c99c24b..c4f3c20 100644
--- a/drivers/firmware/efi/capsule-loader.c
+++ b/drivers/firmware/efi/capsule-loader.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/efi.h>
+#include <linux/vmalloc.h>
 
 #define NO_FURTHER_WRITE_ACTION -1
 
@@ -108,14 +109,15 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
 	int ret;
 	void *cap_hdr_temp;
 
-	cap_hdr_temp = kmap(cap_info->pages[0]);
+	cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
+			VM_MAP, PAGE_KERNEL);
 	if (!cap_hdr_temp) {
 		pr_debug("%s: kmap() failed\n", __func__);
 		return -EFAULT;
 	}
 
 	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
-	kunmap(cap_info->pages[0]);
+	vunmap(cap_hdr_temp);
 	if (ret) {
 		pr_err("%s: efi_capsule_update() failed\n", __func__);
 		return ret;
-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.

Re: [PATCH] efi: capsule: allocate whole capsule into virtual memory

[Matt Fleming]

On Fri, 15 Jul, at 10:41:31AM, Christ, Austin wrote:
> According to UEFI 2.6 section 7.5.3, the capsule should be in contiguous
> virtual memory and firmware may consume the capsule immediately. To
> correctly implement this functionality, the kernel driver needs to vmap
> the entire capsule at the time it is made available to firmware.
> 
> The virtual allocation of the capsule update has been changed from kmap,
> which was only allocating the first page of the update, to vmap and
> allocates the entire data payload.
> 
> Signed-off-by: Austin Christ <austinwc@codeaurora.org>
> ---
>  drivers/firmware/efi/capsule-loader.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
> index c99c24b..c4f3c20 100644
> --- a/drivers/firmware/efi/capsule-loader.c
> +++ b/drivers/firmware/efi/capsule-loader.c
> @@ -16,6 +16,7 @@
>  #include <linux/slab.h>
>  #include <linux/mutex.h>
>  #include <linux/efi.h>
> +#include <linux/vmalloc.h>
>  
>  #define NO_FURTHER_WRITE_ACTION -1
>  
> @@ -108,14 +109,15 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
>  	int ret;
>  	void *cap_hdr_temp;
>  
> -	cap_hdr_temp = kmap(cap_info->pages[0]);
> +	cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
> +			VM_MAP, PAGE_KERNEL);
>  	if (!cap_hdr_temp) {
>  		pr_debug("%s: kmap() failed\n", __func__);
>  		return -EFAULT;
>  	}
>  
>  	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
> -	kunmap(cap_info->pages[0]);
> +	vunmap(cap_hdr_temp);
>  	if (ret) {
>  		pr_err("%s: efi_capsule_update() failed\n", __func__);
>  		return ret;

Looks OK to me but could you also update the comments above
efi_capsule_update() that mention the virtual mapping only being
required for the first page?

Re: [PATCH] efi: capsule: allocate whole capsule into virtual memory

[Christ, Austin]

Hey Matt,


On 7/21/2016 7:12 AM, Matt Fleming wrote:
> On Fri, 15 Jul, at 10:41:31AM, Christ, Austin wrote:
>> According to UEFI 2.6 section 7.5.3, the capsule should be in contiguous
>> virtual memory and firmware may consume the capsule immediately. To
>> correctly implement this functionality, the kernel driver needs to vmap
>> the entire capsule at the time it is made available to firmware.
>>
>> The virtual allocation of the capsule update has been changed from kmap,
>> which was only allocating the first page of the update, to vmap and
>> allocates the entire data payload.
>>
>> Signed-off-by: Austin Christ <austinwc@codeaurora.org>
>> ---
>>   drivers/firmware/efi/capsule-loader.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
>> index c99c24b..c4f3c20 100644
>> --- a/drivers/firmware/efi/capsule-loader.c
>> +++ b/drivers/firmware/efi/capsule-loader.c
>> @@ -16,6 +16,7 @@
>>   #include <linux/slab.h>
>>   #include <linux/mutex.h>
>>   #include <linux/efi.h>
>> +#include <linux/vmalloc.h>
>>   
>>   #define NO_FURTHER_WRITE_ACTION -1
>>   
>> @@ -108,14 +109,15 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
>>   	int ret;
>>   	void *cap_hdr_temp;
>>   
>> -	cap_hdr_temp = kmap(cap_info->pages[0]);
>> +	cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
>> +			VM_MAP, PAGE_KERNEL);
>>   	if (!cap_hdr_temp) {
>>   		pr_debug("%s: kmap() failed\n", __func__);
>>   		return -EFAULT;
>>   	}
>>   
>>   	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
>> -	kunmap(cap_info->pages[0]);
>> +	vunmap(cap_hdr_temp);
>>   	if (ret) {
>>   		pr_err("%s: efi_capsule_update() failed\n", __func__);
>>   		return ret;
> Looks OK to me but could you also update the comments above
> efi_capsule_update() that mention the virtual mapping only being
> required for the first page?
That's a great point. The comments will be updated in v2.

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Thanks,
Austin

Re: [PATCH] efi: capsule: allocate whole capsule into virtual memory

[joeyli]

Hi Austin,

On Fri, Jul 15, 2016 at 10:41:31AM -0600, Austin Christ wrote:
> According to UEFI 2.6 section 7.5.3, the capsule should be in contiguous
> virtual memory and firmware may consume the capsule immediately. To
> correctly implement this functionality, the kernel driver needs to vmap
> the entire capsule at the time it is made available to firmware.
> 
> The virtual allocation of the capsule update has been changed from kmap,
> which was only allocating the first page of the update, to vmap and
> allocates the entire data payload.
> 
> Signed-off-by: Austin Christ <austinwc@codeaurora.org>
> ---
>  drivers/firmware/efi/capsule-loader.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
> index c99c24b..c4f3c20 100644
> --- a/drivers/firmware/efi/capsule-loader.c
> +++ b/drivers/firmware/efi/capsule-loader.c
> @@ -16,6 +16,7 @@
>  #include <linux/slab.h>
>  #include <linux/mutex.h>
>  #include <linux/efi.h>
> +#include <linux/vmalloc.h>
>  
>  #define NO_FURTHER_WRITE_ACTION -1
>  
> @@ -108,14 +109,15 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
>  	int ret;
>  	void *cap_hdr_temp;
>  
> -	cap_hdr_temp = kmap(cap_info->pages[0]);
> +	cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
> +			VM_MAP, PAGE_KERNEL);
>  	if (!cap_hdr_temp) {
>  		pr_debug("%s: kmap() failed\n", __func__);
                             ^^^^^^^^ use vmap()?

I have only a minor suggestion as above.

Reviewed-by: Lee, Chun-Yi <jlee@suse.com>

>  		return -EFAULT;
>  	}
>  
>  	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
> -	kunmap(cap_info->pages[0]);
> +	vunmap(cap_hdr_temp);
>  	if (ret) {
>  		pr_err("%s: efi_capsule_update() failed\n", __func__);
>  		return ret;
> --

Thanks a lot!
Joey Lee 

Re: [PATCH] efi: capsule: allocate whole capsule into virtual memory

[Christ, Austin]

Hello,


On 7/28/2016 12:07 AM, joeyli wrote:
> Hi Austin,
>
> On Fri, Jul 15, 2016 at 10:41:31AM -0600, Austin Christ wrote:
>> According to UEFI 2.6 section 7.5.3, the capsule should be in contiguous
>> virtual memory and firmware may consume the capsule immediately. To
>> correctly implement this functionality, the kernel driver needs to vmap
>> the entire capsule at the time it is made available to firmware.
>>
>> The virtual allocation of the capsule update has been changed from kmap,
>> which was only allocating the first page of the update, to vmap and
>> allocates the entire data payload.
>>
>> Signed-off-by: Austin Christ <austinwc@codeaurora.org>
>> ---
>>   drivers/firmware/efi/capsule-loader.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
>> index c99c24b..c4f3c20 100644
>> --- a/drivers/firmware/efi/capsule-loader.c
>> +++ b/drivers/firmware/efi/capsule-loader.c
>> @@ -16,6 +16,7 @@
>>   #include <linux/slab.h>
>>   #include <linux/mutex.h>
>>   #include <linux/efi.h>
>> +#include <linux/vmalloc.h>
>>   
>>   #define NO_FURTHER_WRITE_ACTION -1
>>   
>> @@ -108,14 +109,15 @@ static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
>>   	int ret;
>>   	void *cap_hdr_temp;
>>   
>> -	cap_hdr_temp = kmap(cap_info->pages[0]);
>> +	cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
>> +			VM_MAP, PAGE_KERNEL);
>>   	if (!cap_hdr_temp) {
>>   		pr_debug("%s: kmap() failed\n", __func__);
>                               ^^^^^^^^ use vmap()?
>
> I have only a minor suggestion as above.
>
> Reviewed-by: Lee, Chun-Yi <jlee@suse.com>

Thanks, this will be fixed in v2.
>
>>   		return -EFAULT;
>>   	}
>>   
>>   	ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
>> -	kunmap(cap_info->pages[0]);
>> +	vunmap(cap_hdr_temp);
>>   	if (ret) {
>>   		pr_err("%s: efi_capsule_update() failed\n", __func__);
>>   		return ret;
>> --
> Thanks a lot!
> Joey Lee
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