[PATCH v5 0/3] Some optimizations related to sgx

[PATCH v5 0/3] Some optimizations related to sgx

[Tianjia Zhang]

This is an optimization of a set of sgx-related codes, each of which
is independent of the patch. Because the second and third patches have
conflicting dependencies, these patches are put together.

---
v5 changes:
  * Remove the two patches with no actual value
  * Typo fix in commit message

v4 changes:
  * Improvements suggested by review

v3 changes:
  * split free_cnt count and spin lock optimization into two patches

v2 changes:
  * review suggested changes

Tianjia Zhang (3):
  selftests/x86: Use getauxval() to simplify the code in sgx
  x86/sgx: Allows ioctl PROVISION to execute before CREATE
  x86/sgx: Remove redundant if conditions in sgx_encl_create

 arch/x86/kernel/cpu/sgx/driver.c   |  1 +
 arch/x86/kernel/cpu/sgx/ioctl.c    |  8 ++++----
 tools/testing/selftests/sgx/main.c | 24 ++++--------------------
 3 files changed, 9 insertions(+), 24 deletions(-)

-- 
2.19.1.3.ge56e4f7

[PATCH v5 1/3] selftests/x86: Use getauxval() to simplify the code in sgx

[Tianjia Zhang]

Simplify the sgx code implemntation by using library function
getauxval() instead of a custom function to get the base address
of vDSO.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
---
 tools/testing/selftests/sgx/main.c | 24 ++++--------------------
 1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
index 724cec700926..5167505fbb46 100644
--- a/tools/testing/selftests/sgx/main.c
+++ b/tools/testing/selftests/sgx/main.c
@@ -15,6 +15,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/auxv.h>
 #include "defines.h"
 #include "main.h"
 #include "../kselftest.h"
@@ -28,24 +29,6 @@ struct vdso_symtab {
 	Elf64_Word *elf_hashtab;
 };
 
-static void *vdso_get_base_addr(char *envp[])
-{
-	Elf64_auxv_t *auxv;
-	int i;
-
-	for (i = 0; envp[i]; i++)
-		;
-
-	auxv = (Elf64_auxv_t *)&envp[i + 1];
-
-	for (i = 0; auxv[i].a_type != AT_NULL; i++) {
-		if (auxv[i].a_type == AT_SYSINFO_EHDR)
-			return (void *)auxv[i].a_un.a_val;
-	}
-
-	return NULL;
-}
-
 static Elf64_Dyn *vdso_get_dyntab(void *addr)
 {
 	Elf64_Ehdr *ehdr = addr;
@@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r
 	return 0;
 }
 
-int main(int argc, char *argv[], char *envp[])
+int main(int argc, char *argv[])
 {
 	struct sgx_enclave_run run;
 	struct vdso_symtab symtab;
@@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[])
 	memset(&run, 0, sizeof(run));
 	run.tcs = encl.encl_base;
 
-	addr = vdso_get_base_addr(envp);
+	/* Get vDSO base address */
+	addr = (void *)getauxval(AT_SYSINFO_EHDR);
 	if (!addr)
 		goto err;
 
-- 
2.19.1.3.ge56e4f7

[PATCH v5 2/3] x86/sgx: Allows ioctl PROVISION to execute before CREATE

[Tianjia Zhang]

In the function sgx_create_enclave(), the direct assignment
operation of attributes_mask determines that the ioctl PROVISION
operation must be executed after the ioctl CREATE operation,
which will limit the flexibility of SGX developers.

This patch takes the assignment of attributes_mask from the
function sgx_create_enclave() has been moved to the function
sgx_open(), this will allow users to perform ioctl PROVISION
operations before ioctl CREATE, increase the flexibility of
the API and reduce restrictions.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
---
 arch/x86/kernel/cpu/sgx/driver.c | 1 +
 arch/x86/kernel/cpu/sgx/ioctl.c  | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index 8ce6d8371cfb..892e2a2a3221 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -36,6 +36,7 @@ static int sgx_open(struct inode *inode, struct file *file)
 		return ret;
 	}
 
+	encl->attributes_mask = SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_KSS;
 	file->private_data = encl;
 
 	return 0;
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 90a5caf76939..1c6ecf9fbeff 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -109,7 +109,6 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 	encl->base = secs->base;
 	encl->size = secs->size;
 	encl->attributes = secs->attributes;
-	encl->attributes_mask = SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_KSS;
 
 	/* Set only after completion, as encl->lock has not been taken. */
 	set_bit(SGX_ENCL_CREATED, &encl->flags);
-- 
2.19.1.3.ge56e4f7

[PATCH v5 3/3] x86/sgx: Remove redundant if conditions in sgx_encl_create

[Tianjia Zhang]

In this scenario, there is no case where va_page is NULL, and
the error has been checked. The if-condition statement here is
redundant, so remove the condition detection.

Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
---
 arch/x86/kernel/cpu/sgx/ioctl.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 1c6ecf9fbeff..719c21cca569 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -66,9 +66,10 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 	va_page = sgx_encl_grow(encl);
 	if (IS_ERR(va_page))
 		return PTR_ERR(va_page);
-	else if (va_page)
-		list_add(&va_page->list, &encl->va_pages);
-	/* else the tail page of the VA page list had free slots. */
+	if (!va_page)
+		return -EIO;
+
+	list_add(&va_page->list, &encl->va_pages);
 
 	/* The extra page goes to SECS. */
 	encl_size = secs->size + PAGE_SIZE;
-- 
2.19.1.3.ge56e4f7

Re: [PATCH v5 3/3] x86/sgx: Remove redundant if conditions in sgx_encl_create

[Jarkko Sakkinen]

On Tue, Feb 16, 2021 at 11:31:33AM +0800, Tianjia Zhang wrote:
> In this scenario, there is no case where va_page is NULL, and
> the error has been checked. The if-condition statement here is
> redundant, so remove the condition detection.
> 
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
>  arch/x86/kernel/cpu/sgx/ioctl.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index 1c6ecf9fbeff..719c21cca569 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -66,9 +66,10 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
>  	va_page = sgx_encl_grow(encl);
>  	if (IS_ERR(va_page))
>  		return PTR_ERR(va_page);
> -	else if (va_page)
> -		list_add(&va_page->list, &encl->va_pages);
> -	/* else the tail page of the VA page list had free slots. */
> +	if (!va_page)
> +		return -EIO;

Why this check?

> +
> +	list_add(&va_page->list, &encl->va_pages);
>  
>  	/* The extra page goes to SECS. */
>  	encl_size = secs->size + PAGE_SIZE;
> -- 
> 2.19.1.3.ge56e4f7
> 
> 

/Jarkko

Re: [PATCH v5 3/3] x86/sgx: Remove redundant if conditions in sgx_encl_create

[Tianjia Zhang]

On 2/16/21 4:29 PM, Jarkko Sakkinen wrote:
> On Tue, Feb 16, 2021 at 11:31:33AM +0800, Tianjia Zhang wrote:
>> In this scenario, there is no case where va_page is NULL, and
>> the error has been checked. The if-condition statement here is
>> redundant, so remove the condition detection.
>>
>> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
>> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
>> ---
>>   arch/x86/kernel/cpu/sgx/ioctl.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
>> index 1c6ecf9fbeff..719c21cca569 100644
>> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
>> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
>> @@ -66,9 +66,10 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
>>   	va_page = sgx_encl_grow(encl);
>>   	if (IS_ERR(va_page))
>>   		return PTR_ERR(va_page);
>> -	else if (va_page)
>> -		list_add(&va_page->list, &encl->va_pages);
>> -	/* else the tail page of the VA page list had free slots. */
>> +	if (!va_page)
>> +		return -EIO;
> 
> Why this check?
> 

The value of va_page may be a negative error value, it may be NULL, or 
it may be a valid pointer, so check this return value.

Tianjia

>> +
>> +	list_add(&va_page->list, &encl->va_pages);
>>   
>>   	/* The extra page goes to SECS. */
>>   	encl_size = secs->size + PAGE_SIZE;
>> -- 
>> 2.19.1.3.ge56e4f7
>>
>>
> 
> /Jarkko
>