diff mbox series

[RFC,v3,03/10] x86/sgx: Save enclave pointer for VA page

Message ID 20220401142409.26215-4-cathy.zhang@intel.com (mailing list archive)
State New, archived
Headers show
Series Support microcode updates affecting SGX | expand

Commit Message

Zhang, Cathy April 1, 2022, 2:24 p.m. UTC
Tearing down all enclaves is required by SGX SVN update, which
involves running the ENCLS[EREMOVE] instruction on every EPC
page. This (tearing down all enclaves) should be coordinated
with any enclaves that may be in the process of existing and thus
already be running ENCLS[EREMOVE] as part of enclave release.

In support of this coordination, it is required to know which enclave
owns each in-use EPC page. It is already possible to locate the
owning enclave of SECS and regular pages but not for VA pages.

Save the enclave pointer for each VA page to support locating its
owning enclave.

Note: to track 2T EPC memory, this scheme of tracking will use
additional 8M memory.

Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
---
 arch/x86/kernel/cpu/sgx/encl.h  | 1 +
 arch/x86/kernel/cpu/sgx/ioctl.c | 1 +
 2 files changed, 2 insertions(+)

Comments

Jarkko Sakkinen April 3, 2022, 10:08 a.m. UTC | #1
On Fri, Apr 01, 2022 at 10:24:02PM +0800, Cathy Zhang wrote:
> Tearing down all enclaves is required by SGX SVN update, which
> involves running the ENCLS[EREMOVE] instruction on every EPC
> page. This (tearing down all enclaves) should be coordinated
> with any enclaves that may be in the process of existing and thus
> already be running ENCLS[EREMOVE] as part of enclave release.
> 
> In support of this coordination, it is required to know which enclave
> owns each in-use EPC page. It is already possible to locate the
> owning enclave of SECS and regular pages but not for VA pages.
> 
> Save the enclave pointer for each VA page to support locating its
> owning enclave.
> 
> Note: to track 2T EPC memory, this scheme of tracking will use
> additional 8M memory.
> 
> Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
> ---
>  arch/x86/kernel/cpu/sgx/encl.h  | 1 +
>  arch/x86/kernel/cpu/sgx/ioctl.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
> index 0c8571fc30cf..59fbd4ed5c64 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.h
> +++ b/arch/x86/kernel/cpu/sgx/encl.h
> @@ -76,6 +76,7 @@ struct sgx_va_page {
>  	struct sgx_epc_page *epc_page;
>  	DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
>  	struct list_head list;
> +	struct sgx_encl *encl;
>  };
>  
>  struct sgx_backing {
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index f0ce96bd462a..da82abbb81b4 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -30,6 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
>  		if (!va_page)
>  			return ERR_PTR(-ENOMEM);
>  
> +		va_page->encl = encl;
>  		va_page->epc_page = sgx_alloc_va_page(va_page);
>  		if (IS_ERR(va_page->epc_page)) {
>  			err = ERR_CAST(va_page->epc_page);
> -- 
> 2.17.1
> 

Squash this with the previous patch. Then the code will provide
answer to one of the questions that I mentioned in 2/10 review.

BR, Jarkko
Zhang, Cathy April 6, 2022, 3:31 a.m. UTC | #2
> -----Original Message-----
> From: Jarkko Sakkinen <jarkko@kernel.org>
> Sent: Sunday, April 3, 2022 6:08 PM
> To: Zhang, Cathy <cathy.zhang@intel.com>
> Cc: linux-sgx@vger.kernel.org; x86@kernel.org; Chatre, Reinette
> <reinette.chatre@intel.com>; Hansen, Dave <dave.hansen@intel.com>; Raj,
> Ashok <ashok.raj@intel.com>
> Subject: Re: [RFC PATCH v3 03/10] x86/sgx: Save enclave pointer for VA page
> 
> On Fri, Apr 01, 2022 at 10:24:02PM +0800, Cathy Zhang wrote:
> > Tearing down all enclaves is required by SGX SVN update, which
> > involves running the ENCLS[EREMOVE] instruction on every EPC page.
> > This (tearing down all enclaves) should be coordinated with any
> > enclaves that may be in the process of existing and thus already be
> > running ENCLS[EREMOVE] as part of enclave release.
> >
> > In support of this coordination, it is required to know which enclave
> > owns each in-use EPC page. It is already possible to locate the owning
> > enclave of SECS and regular pages but not for VA pages.
> >
> > Save the enclave pointer for each VA page to support locating its
> > owning enclave.
> >
> > Note: to track 2T EPC memory, this scheme of tracking will use
> > additional 8M memory.
> >
> > Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
> > ---
> >  arch/x86/kernel/cpu/sgx/encl.h  | 1 +
> > arch/x86/kernel/cpu/sgx/ioctl.c | 1 +
> >  2 files changed, 2 insertions(+)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/encl.h
> > b/arch/x86/kernel/cpu/sgx/encl.h index 0c8571fc30cf..59fbd4ed5c64
> > 100644
> > --- a/arch/x86/kernel/cpu/sgx/encl.h
> > +++ b/arch/x86/kernel/cpu/sgx/encl.h
> > @@ -76,6 +76,7 @@ struct sgx_va_page {
> >  	struct sgx_epc_page *epc_page;
> >  	DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
> >  	struct list_head list;
> > +	struct sgx_encl *encl;
> >  };
> >
> >  struct sgx_backing {
> > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c
> > b/arch/x86/kernel/cpu/sgx/ioctl.c index f0ce96bd462a..da82abbb81b4
> > 100644
> > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > @@ -30,6 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct
> sgx_encl *encl)
> >  		if (!va_page)
> >  			return ERR_PTR(-ENOMEM);
> >
> > +		va_page->encl = encl;
> >  		va_page->epc_page = sgx_alloc_va_page(va_page);
> >  		if (IS_ERR(va_page->epc_page)) {
> >  			err = ERR_CAST(va_page->epc_page);
> > --
> > 2.17.1
> >
> 
> Squash this with the previous patch. Then the code will provide
> answer to one of the questions that I mentioned in 2/10 review.
> 
> BR, Jarkko

Squashed. How about re-write the commit log as follows:

x86/sgx: Save enclave pointer for VA page

Tearing down all enclaves is required by SGX SVN update, which
involves running the ENCLS[EREMOVE] instruction on every EPC
page. This (tearing down all enclaves) should be coordinated
with any enclaves that may be in the process of existing and thus
already be running ENCLS[EREMOVE] as part of enclave release.

In support of this coordination, it is required to know which enclave
owns each in-use EPC page. It is already possible to locate the
owning enclave of SECS and regular pages but not for VA pages.

Make the following changes for VA page's location:
1) Make epc->owner type-agnostic by change its type to 'void *'. So,
   besides "struct sgx_encl_page", it can have other types, like
   "struct sgx_va_page".
2) Save the enclave pointer for each VA page to support locating its
   owning enclave.

Note: to track 2T EPC memory, this scheme of tracking will use
additional 8M memory.
Jarkko Sakkinen April 6, 2022, 6:33 a.m. UTC | #3
On Wed, 2022-04-06 at 03:31 +0000, Zhang, Cathy wrote:
> 
> 
> > -----Original Message-----
> > From: Jarkko Sakkinen <jarkko@kernel.org>
> > Sent: Sunday, April 3, 2022 6:08 PM
> > To: Zhang, Cathy <cathy.zhang@intel.com>
> > Cc: linux-sgx@vger.kernel.org; x86@kernel.org; Chatre, Reinette
> > <reinette.chatre@intel.com>; Hansen, Dave <dave.hansen@intel.com>; Raj,
> > Ashok <ashok.raj@intel.com>
> > Subject: Re: [RFC PATCH v3 03/10] x86/sgx: Save enclave pointer for VA page
> > 
> > On Fri, Apr 01, 2022 at 10:24:02PM +0800, Cathy Zhang wrote:
> > > Tearing down all enclaves is required by SGX SVN update, which
> > > involves running the ENCLS[EREMOVE] instruction on every EPC page.
> > > This (tearing down all enclaves) should be coordinated with any
> > > enclaves that may be in the process of existing and thus already be
> > > running ENCLS[EREMOVE] as part of enclave release.
> > > 
> > > In support of this coordination, it is required to know which enclave
> > > owns each in-use EPC page. It is already possible to locate the owning
> > > enclave of SECS and regular pages but not for VA pages.
> > > 
> > > Save the enclave pointer for each VA page to support locating its
> > > owning enclave.
> > > 
> > > Note: to track 2T EPC memory, this scheme of tracking will use
> > > additional 8M memory.
> > > 
> > > Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
> > > ---
> > >  arch/x86/kernel/cpu/sgx/encl.h  | 1 +
> > > arch/x86/kernel/cpu/sgx/ioctl.c | 1 +
> > >  2 files changed, 2 insertions(+)
> > > 
> > > diff --git a/arch/x86/kernel/cpu/sgx/encl.h
> > > b/arch/x86/kernel/cpu/sgx/encl.h index 0c8571fc30cf..59fbd4ed5c64
> > > 100644
> > > --- a/arch/x86/kernel/cpu/sgx/encl.h
> > > +++ b/arch/x86/kernel/cpu/sgx/encl.h
> > > @@ -76,6 +76,7 @@ struct sgx_va_page {
> > >         struct sgx_epc_page *epc_page;
> > >         DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
> > >         struct list_head list;
> > > +       struct sgx_encl *encl;
> > >  };
> > > 
> > >  struct sgx_backing {
> > > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c
> > > b/arch/x86/kernel/cpu/sgx/ioctl.c index f0ce96bd462a..da82abbb81b4
> > > 100644
> > > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > > @@ -30,6 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct
> > sgx_encl *encl)
> > >                 if (!va_page)
> > >                         return ERR_PTR(-ENOMEM);
> > > 
> > > +               va_page->encl = encl;
> > >                 va_page->epc_page = sgx_alloc_va_page(va_page);
> > >                 if (IS_ERR(va_page->epc_page)) {
> > >                         err = ERR_CAST(va_page->epc_page);
> > > --
> > > 2.17.1
> > > 
> > 
> > Squash this with the previous patch. Then the code will provide
> > answer to one of the questions that I mentioned in 2/10 review.
> > 
> > BR, Jarkko
> 
> Squashed. How about re-write the commit log as follows:
> 
> x86/sgx: Save enclave pointer for VA page
> 
> Tearing down all enclaves is required by SGX SVN update, which
> involves running the ENCLS[EREMOVE] instruction on every EPC
> page. This (tearing down all enclaves) should be coordinated
> with any enclaves that may be in the process of existing and thus
> already be running ENCLS[EREMOVE] as part of enclave release.
> 
> In support of this coordination, it is required to know which enclave
> owns each in-use EPC page. It is already possible to locate the
> owning enclave of SECS and regular pages but not for VA pages.
> 
> Make the following changes for VA page's location:
> 1) Make epc->owner type-agnostic by change its type to 'void *'. So,
>    besides "struct sgx_encl_page", it can have other types, like
>    "struct sgx_va_page".
> 2) Save the enclave pointer for each VA page to support locating its
>    owning enclave.
> 
> Note: to track 2T EPC memory, this scheme of tracking will use
> additional 8M memory.

Sounds good to me.

BR, Jarkko
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 0c8571fc30cf..59fbd4ed5c64 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -76,6 +76,7 @@  struct sgx_va_page {
 	struct sgx_epc_page *epc_page;
 	DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
 	struct list_head list;
+	struct sgx_encl *encl;
 };
 
 struct sgx_backing {
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index f0ce96bd462a..da82abbb81b4 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -30,6 +30,7 @@  static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
 		if (!va_page)
 			return ERR_PTR(-ENOMEM);
 
+		va_page->encl = encl;
 		va_page->epc_page = sgx_alloc_va_page(va_page);
 		if (IS_ERR(va_page->epc_page)) {
 			err = ERR_CAST(va_page->epc_page);