2019-05-08 14:50:35

by Kirill A. Shutemov

Subject: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

From: Kai Huang <[email protected]>

KVM needs those variables to get/set memory encryption mask.

Signed-off-by: Kai Huang <[email protected]>
Signed-off-by: Kirill A. Shutemov <[email protected]>
---
arch/x86/mm/mktme.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
index df70651816a1..12f4266cf7ea 100644
--- a/arch/x86/mm/mktme.c
+++ b/arch/x86/mm/mktme.c
@@ -7,13 +7,16 @@

/* Mask to extract KeyID from physical address. */
phys_addr_t mktme_keyid_mask;
+EXPORT_SYMBOL_GPL(mktme_keyid_mask);
/*
* Number of KeyIDs available for MKTME.
* Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
*/
int mktme_nr_keyids;
+EXPORT_SYMBOL_GPL(mktme_nr_keyids);
/* Shift of KeyID within physical address. */
int mktme_keyid_shift;
+EXPORT_SYMBOL_GPL(mktme_keyid_shift);

DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
EXPORT_SYMBOL_GPL(mktme_enabled_key);
--
2.20.1

2019-06-14 11:57:24

by Peter Zijlstra

Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote:
> From: Kai Huang <[email protected]>
>
> KVM needs those variables to get/set memory encryption mask.
>
> Signed-off-by: Kai Huang <[email protected]>
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> ---
> arch/x86/mm/mktme.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> index df70651816a1..12f4266cf7ea 100644
> --- a/arch/x86/mm/mktme.c
> +++ b/arch/x86/mm/mktme.c
> @@ -7,13 +7,16 @@
>
> /* Mask to extract KeyID from physical address. */
> phys_addr_t mktme_keyid_mask;
> +EXPORT_SYMBOL_GPL(mktme_keyid_mask);
> /*
> * Number of KeyIDs available for MKTME.
> * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
> */
> int mktme_nr_keyids;
> +EXPORT_SYMBOL_GPL(mktme_nr_keyids);
> /* Shift of KeyID within physical address. */
> int mktme_keyid_shift;
> +EXPORT_SYMBOL_GPL(mktme_keyid_shift);
>
> DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
> EXPORT_SYMBOL_GPL(mktme_enabled_key);

NAK, don't export variables. Who owns the values, who enforces this?

2019-06-17 03:14:54

by Kai Huang

Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote:
> On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote:
> > From: Kai Huang <[email protected]>
> >
> > KVM needs those variables to get/set memory encryption mask.
> >
> > Signed-off-by: Kai Huang <[email protected]>
> > Signed-off-by: Kirill A. Shutemov <[email protected]>
> > ---
> > arch/x86/mm/mktme.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> > index df70651816a1..12f4266cf7ea 100644
> > --- a/arch/x86/mm/mktme.c
> > +++ b/arch/x86/mm/mktme.c
> > @@ -7,13 +7,16 @@
> >
> > /* Mask to extract KeyID from physical address. */
> > phys_addr_t mktme_keyid_mask;
> > +EXPORT_SYMBOL_GPL(mktme_keyid_mask);
> > /*
> > * Number of KeyIDs available for MKTME.
> > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
> > */
> > int mktme_nr_keyids;
> > +EXPORT_SYMBOL_GPL(mktme_nr_keyids);
> > /* Shift of KeyID within physical address. */
> > int mktme_keyid_shift;
> > +EXPORT_SYMBOL_GPL(mktme_keyid_shift);
> >
> > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
> > EXPORT_SYMBOL_GPL(mktme_enabled_key);
>
> NAK, don't export variables. Who owns the values, who enforces this?
>

Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the right
place in the PTE (of KVM EPT and VT-d DMA page table).

MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID.

Maybe better to introduce functions instead of exposing variables directly?

Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds
"page_keyid() << mktme_keyid_shift"?

Thanks,
-Kai

2019-06-17 07:47:16

by Peter Zijlstra

Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

On Mon, Jun 17, 2019 at 03:14:29PM +1200, Kai Huang wrote:
> On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote:
> > On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote:
> > > From: Kai Huang <[email protected]>
> > >
> > > KVM needs those variables to get/set memory encryption mask.
> > >
> > > Signed-off-by: Kai Huang <[email protected]>
> > > Signed-off-by: Kirill A. Shutemov <[email protected]>
> > > ---
> > > arch/x86/mm/mktme.c | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> > > index df70651816a1..12f4266cf7ea 100644
> > > --- a/arch/x86/mm/mktme.c
> > > +++ b/arch/x86/mm/mktme.c
> > > @@ -7,13 +7,16 @@
> > >
> > > /* Mask to extract KeyID from physical address. */
> > > phys_addr_t mktme_keyid_mask;
> > > +EXPORT_SYMBOL_GPL(mktme_keyid_mask);
> > > /*
> > > * Number of KeyIDs available for MKTME.
> > > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
> > > */
> > > int mktme_nr_keyids;
> > > +EXPORT_SYMBOL_GPL(mktme_nr_keyids);
> > > /* Shift of KeyID within physical address. */
> > > int mktme_keyid_shift;
> > > +EXPORT_SYMBOL_GPL(mktme_keyid_shift);
> > >
> > > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
> > > EXPORT_SYMBOL_GPL(mktme_enabled_key);
> >
> > NAK, don't export variables. Who owns the values, who enforces this?
> >
>
> Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the right
> place in the PTE (of KVM EPT and VT-d DMA page table).
>
> MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID.
>
> Maybe better to introduce functions instead of exposing variables directly?
>
> Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds
> "page_keyid() << mktme_keyid_shift"?

Yes, that's much better, because that strictly limits the access to R/O.

2019-06-17 08:41:34

by Kai Huang

Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

On Mon, 2019-06-17 at 09:46 +0200, Peter Zijlstra wrote:
> On Mon, Jun 17, 2019 at 03:14:29PM +1200, Kai Huang wrote:
> > On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote:
> > > On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote:
> > > > From: Kai Huang <[email protected]>
> > > >
> > > > KVM needs those variables to get/set memory encryption mask.
> > > >
> > > > Signed-off-by: Kai Huang <[email protected]>
> > > > Signed-off-by: Kirill A. Shutemov <[email protected]>
> > > > ---
> > > > arch/x86/mm/mktme.c | 3 +++
> > > > 1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> > > > index df70651816a1..12f4266cf7ea 100644
> > > > --- a/arch/x86/mm/mktme.c
> > > > +++ b/arch/x86/mm/mktme.c
> > > > @@ -7,13 +7,16 @@
> > > >
> > > > /* Mask to extract KeyID from physical address. */
> > > > phys_addr_t mktme_keyid_mask;
> > > > +EXPORT_SYMBOL_GPL(mktme_keyid_mask);
> > > > /*
> > > > * Number of KeyIDs available for MKTME.
> > > > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
> > > > */
> > > > int mktme_nr_keyids;
> > > > +EXPORT_SYMBOL_GPL(mktme_nr_keyids);
> > > > /* Shift of KeyID within physical address. */
> > > > int mktme_keyid_shift;
> > > > +EXPORT_SYMBOL_GPL(mktme_keyid_shift);
> > > >
> > > > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
> > > > EXPORT_SYMBOL_GPL(mktme_enabled_key);
> > >
> > > NAK, don't export variables. Who owns the values, who enforces this?
> > >
> >
> > Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the
> > right
> > place in the PTE (of KVM EPT and VT-d DMA page table).
> >
> > MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID.
> >
> > Maybe better to introduce functions instead of exposing variables directly?
> >
> > Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds
> > "page_keyid() << mktme_keyid_shift"?
>
> Yes, that's much better, because that strictly limits the access to R/O.
>

Thanks. I think Kirill will be the one to handle your suggestion. :)

Kirill?

Thanks,
-Kai

2019-06-17 11:25:38

by Kirill A. Shutemov

Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables

On Mon, Jun 17, 2019 at 08:39:43PM +1200, Kai Huang wrote:
> On Mon, 2019-06-17 at 09:46 +0200, Peter Zijlstra wrote:
> > On Mon, Jun 17, 2019 at 03:14:29PM +1200, Kai Huang wrote:
> > > On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote:
> > > > On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote:
> > > > > From: Kai Huang <[email protected]>
> > > > >
> > > > > KVM needs those variables to get/set memory encryption mask.
> > > > >
> > > > > Signed-off-by: Kai Huang <[email protected]>
> > > > > Signed-off-by: Kirill A. Shutemov <[email protected]>
> > > > > ---
> > > > > arch/x86/mm/mktme.c | 3 +++
> > > > > 1 file changed, 3 insertions(+)
> > > > >
> > > > > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> > > > > index df70651816a1..12f4266cf7ea 100644
> > > > > --- a/arch/x86/mm/mktme.c
> > > > > +++ b/arch/x86/mm/mktme.c
> > > > > @@ -7,13 +7,16 @@
> > > > >
> > > > > /* Mask to extract KeyID from physical address. */
> > > > > phys_addr_t mktme_keyid_mask;
> > > > > +EXPORT_SYMBOL_GPL(mktme_keyid_mask);
> > > > > /*
> > > > > * Number of KeyIDs available for MKTME.
> > > > > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1.
> > > > > */
> > > > > int mktme_nr_keyids;
> > > > > +EXPORT_SYMBOL_GPL(mktme_nr_keyids);
> > > > > /* Shift of KeyID within physical address. */
> > > > > int mktme_keyid_shift;
> > > > > +EXPORT_SYMBOL_GPL(mktme_keyid_shift);
> > > > >
> > > > > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key);
> > > > > EXPORT_SYMBOL_GPL(mktme_enabled_key);
> > > >
> > > > NAK, don't export variables. Who owns the values, who enforces this?
> > > >
> > >
> > > Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the
> > > right
> > > place in the PTE (of KVM EPT and VT-d DMA page table).
> > >
> > > MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID.
> > >
> > > Maybe better to introduce functions instead of exposing variables directly?
> > >
> > > Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds
> > > "page_keyid() << mktme_keyid_shift"?
> >
> > Yes, that's much better, because that strictly limits the access to R/O.
> >
>
> Thanks. I think Kirill will be the one to handle your suggestion. :)
>
> Kirill?

Will do.

--
Kirill A. Shutemov