diff mbox series

[XEN,v7,16/20] xen/arm: ffa: add defines for sharing memory

Message ID ad85591c42f4db3c3001ae4b5572c1096c159593.1677079672.git.jens.wiklander@linaro.org (mailing list archive)
State Superseded
Headers show
Series Xen FF-A mediator | expand

Commit Message

Jens Wiklander Feb. 22, 2023, 3:33 p.m. UTC 
Adds defines needed for sharing using the function FFA_MEM_SHARE and
friends.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 xen/arch/arm/tee/ffa.c | 57 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

Comments

Bertrand Marquis March 3, 2023, 1:38 p.m. UTC | #1 
Hi Jens,

> On 22 Feb 2023, at 16:33, Jens Wiklander <jens.wiklander@linaro.org> wrote:
> 
> Adds defines needed for sharing using the function FFA_MEM_SHARE and
> friends.
> 
> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> ---
> xen/arch/arm/tee/ffa.c | 57 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
> 
> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> index 3571817c0bcd..bfd378f7fcd7 100644
> --- a/xen/arch/arm/tee/ffa.c
> +++ b/xen/arch/arm/tee/ffa.c
> @@ -22,6 +22,14 @@
> #include <asm/tee/ffa.h>
> #include <asm/regs.h>
> 
> +/*
> + * References:
> + * FF-A-1.0-REL: FF-A specification version 1.0 available at
> + *               https://developer.arm.com/documentation/den0077/a
> + * FF-A-1.1-REL0: FF-A specification version 1.1 available at
> + *                https://developer.arm.com/documentation/den0077/e
> + */

This could actually be directly in the file header.

> +
> /* Error codes */
> #define FFA_RET_OK                      0
> #define FFA_RET_NOT_SUPPORTED           -1
> @@ -66,6 +74,55 @@
>  */
> #define FFA_PAGE_SIZE                   SZ_4K
> 
> +/*
> + * Limit for shared buffer size. Please note that this define limits
> + * number of pages. But user buffer can be not aligned to a page
> + * boundary. So it is possible that user would not be able to share
> + * exactly FFA_MAX_SHM_BUFFER_PG * FFA_PAGE_SIZE bytes.
> + *
> + * FF-A doesn't have any direct requirments on GlobalPlatform or vice
> + * versa, but an implementation can very well use FF-A in order to provide
> + * a GlobalPlatform interface on top.
> + *
> + * Global Platform specification for TEE requires that any TEE
> + * implementation should allow to share buffers with size of at least
> + * 512KB. Due to align issue mentioned above, we need to increase this
> + * value with one.

Could you give a bit more details here: what spec version, where in the spec ?

I did download one version of it and at a first glance could not find this value.

> + */
> +#define FFA_MAX_SHM_PAGE_COUNT          (SZ_512K / FFA_PAGE_SIZE + 1)
> +
> +/*
> + * Limits the number of shared buffers that guest can have at once. This
> + * is to prevent case, when guests tricks XEN into exhausting its own
> + * memory by allocating many small buffers. This value has been chosen
> + * arbitrary.
> + */
> +#define FFA_MAX_SHM_COUNT               32

For those 2 limits, I am a bit wondering which should be defined in the code or maybe
configurable in kconfig or through xen command line or per guest.

I do not think we can answer that now but if one of these limits is reached we should
have a clear error message so that we could easily say what to modify and decide
if/how to solve it.


> +
> +/* FF-A-1.1-REL0 section 10.9.2 Memory region handle, page 167 */
> +#define FFA_HANDLE_HYP_FLAG             BIT(63, ULL)
> +#define FFA_HANDLE_INVALID              0xffffffffffffffffULL
> +
> +/*
> + * The bits for FFA_NORMAL_MEM_REG_ATTR FFA_MEM_ACC_RW below are
> + * defined in FF-A-1.1-REL0 Table 10.18 at page 175.
> + */
> + /* Memory attributes: Normal memory, Write-Back cacheable, Inner shareable */
> +#define FFA_NORMAL_MEM_REG_ATTR         0x2fU
> +/* Memory access permissions: Read-write */
> +#define FFA_MEM_ACC_RW                  0x2U

RW bits are defined in table 10.15 at page 168 if i am not mistaking

> +
> +/* FF-A-1.1-REL0 section 10.11.4 Flags usage, page 184-187 */
> +/* Clear memory before mapping in receiver */
> +#define FFA_MEMORY_REGION_FLAG_CLEAR            BIT(0, U)
> +/* Relayer may time slice this operation */
> +#define FFA_MEMORY_REGION_FLAG_TIME_SLICE       BIT(1, U)
> +/* Clear memory after receiver relinquishes it */
> +#define FFA_MEMORY_REGION_FLAG_CLEAR_RELINQUISH BIT(2, U)
> +/* Share memory transaction */
> +#define FFA_MEMORY_REGION_TRANSACTION_TYPE_SHARE (1U << 3)
> +
> +
Please only add one empty line here.

I checked the definitions and they are all coherent with the spec.

Cheers
Bertrand

> /* Framework direct request/response */
> #define FFA_MSG_FLAG_FRAMEWORK          BIT(31, U)
> #define FFA_MSG_TYPE_MASK               0xFFU;
> -- 
> 2.34.1
>
Jens Wiklander March 3, 2023, 4:51 p.m. UTC | #2 
Hi Bertrand,

On Fri, Mar 3, 2023 at 2:38 PM Bertrand Marquis
<Bertrand.Marquis@arm.com> wrote:
>
> Hi Jens,
>
> > On 22 Feb 2023, at 16:33, Jens Wiklander <jens.wiklander@linaro.org> wrote:
> >
> > Adds defines needed for sharing using the function FFA_MEM_SHARE and
> > friends.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> > ---
> > xen/arch/arm/tee/ffa.c | 57 ++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 57 insertions(+)
> >
> > diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> > index 3571817c0bcd..bfd378f7fcd7 100644
> > --- a/xen/arch/arm/tee/ffa.c
> > +++ b/xen/arch/arm/tee/ffa.c
> > @@ -22,6 +22,14 @@
> > #include <asm/tee/ffa.h>
> > #include <asm/regs.h>
> >
> > +/*
> > + * References:
> > + * FF-A-1.0-REL: FF-A specification version 1.0 available at
> > + *               https://developer.arm.com/documentation/den0077/a
> > + * FF-A-1.1-REL0: FF-A specification version 1.1 available at
> > + *                https://developer.arm.com/documentation/den0077/e
> > + */
>
> This could actually be directly in the file header.

OK, I'll move it.

>
> > +
> > /* Error codes */
> > #define FFA_RET_OK                      0
> > #define FFA_RET_NOT_SUPPORTED           -1
> > @@ -66,6 +74,55 @@
> >  */
> > #define FFA_PAGE_SIZE                   SZ_4K
> >
> > +/*
> > + * Limit for shared buffer size. Please note that this define limits
> > + * number of pages. But user buffer can be not aligned to a page
> > + * boundary. So it is possible that user would not be able to share
> > + * exactly FFA_MAX_SHM_BUFFER_PG * FFA_PAGE_SIZE bytes.
> > + *
> > + * FF-A doesn't have any direct requirments on GlobalPlatform or vice
> > + * versa, but an implementation can very well use FF-A in order to provide
> > + * a GlobalPlatform interface on top.
> > + *
> > + * Global Platform specification for TEE requires that any TEE
> > + * implementation should allow to share buffers with size of at least
> > + * 512KB. Due to align issue mentioned above, we need to increase this
> > + * value with one.
>
> Could you give a bit more details here: what spec version, where in the spec ?
>
> I did download one version of it and at a first glance could not find this value.

https://globalplatform.org/specs-library/tee-client-api-specification/
TEE Client API Specification version 1.0c, page 24, Table 4-1: API
Configuration Constants, look for TEEC_CONFIG_SHAREDMEM_MAX_SIZE. I'll
add a reference.

>
> > + */
> > +#define FFA_MAX_SHM_PAGE_COUNT          (SZ_512K / FFA_PAGE_SIZE + 1)
> > +
> > +/*
> > + * Limits the number of shared buffers that guest can have at once. This
> > + * is to prevent case, when guests tricks XEN into exhausting its own
> > + * memory by allocating many small buffers. This value has been chosen
> > + * arbitrary.
> > + */
> > +#define FFA_MAX_SHM_COUNT               32
>
> For those 2 limits, I am a bit wondering which should be defined in the code or maybe
> configurable in kconfig or through xen command line or per guest.

Per guest sounds like an interesting option when these values aren't
good enough.

>
> I do not think we can answer that now but if one of these limits is reached we should
> have a clear error message so that we could easily say what to modify and decide
> if/how to solve it.

I'll add prints in the later patches.

>
>
> > +
> > +/* FF-A-1.1-REL0 section 10.9.2 Memory region handle, page 167 */
> > +#define FFA_HANDLE_HYP_FLAG             BIT(63, ULL)
> > +#define FFA_HANDLE_INVALID              0xffffffffffffffffULL
> > +
> > +/*
> > + * The bits for FFA_NORMAL_MEM_REG_ATTR FFA_MEM_ACC_RW below are
> > + * defined in FF-A-1.1-REL0 Table 10.18 at page 175.
> > + */
> > + /* Memory attributes: Normal memory, Write-Back cacheable, Inner shareable */
> > +#define FFA_NORMAL_MEM_REG_ATTR         0x2fU
> > +/* Memory access permissions: Read-write */
> > +#define FFA_MEM_ACC_RW                  0x2U
>
> RW bits are defined in table 10.15 at page 168 if i am not mistaking

Thanks, I'll update it.

>
> > +
> > +/* FF-A-1.1-REL0 section 10.11.4 Flags usage, page 184-187 */
> > +/* Clear memory before mapping in receiver */
> > +#define FFA_MEMORY_REGION_FLAG_CLEAR            BIT(0, U)
> > +/* Relayer may time slice this operation */
> > +#define FFA_MEMORY_REGION_FLAG_TIME_SLICE       BIT(1, U)
> > +/* Clear memory after receiver relinquishes it */
> > +#define FFA_MEMORY_REGION_FLAG_CLEAR_RELINQUISH BIT(2, U)
> > +/* Share memory transaction */
> > +#define FFA_MEMORY_REGION_TRANSACTION_TYPE_SHARE (1U << 3)
> > +
> > +
> Please only add one empty line here.

OK, I'll fix.

>
> I checked the definitions and they are all coherent with the spec.

Thanks,
Jens

>
> Cheers
> Bertrand
>
> > /* Framework direct request/response */
> > #define FFA_MSG_FLAG_FRAMEWORK          BIT(31, U)
> > #define FFA_MSG_TYPE_MASK               0xFFU;
> > --
> > 2.34.1
> >
>
diff mbox series

Patch

diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
index 3571817c0bcd..bfd378f7fcd7 100644
--- a/xen/arch/arm/tee/ffa.c
+++ b/xen/arch/arm/tee/ffa.c
@@ -22,6 +22,14 @@ 
 #include <asm/tee/ffa.h>
 #include <asm/regs.h>
 
+/*
+ * References:
+ * FF-A-1.0-REL: FF-A specification version 1.0 available at
+ *               https://developer.arm.com/documentation/den0077/a
+ * FF-A-1.1-REL0: FF-A specification version 1.1 available at
+ *                https://developer.arm.com/documentation/den0077/e
+ */
+
 /* Error codes */
 #define FFA_RET_OK                      0
 #define FFA_RET_NOT_SUPPORTED           -1
@@ -66,6 +74,55 @@ 
  */
 #define FFA_PAGE_SIZE                   SZ_4K
 
+/*
+ * Limit for shared buffer size. Please note that this define limits
+ * number of pages. But user buffer can be not aligned to a page
+ * boundary. So it is possible that user would not be able to share
+ * exactly FFA_MAX_SHM_BUFFER_PG * FFA_PAGE_SIZE bytes.
+ *
+ * FF-A doesn't have any direct requirments on GlobalPlatform or vice
+ * versa, but an implementation can very well use FF-A in order to provide
+ * a GlobalPlatform interface on top.
+ *
+ * Global Platform specification for TEE requires that any TEE
+ * implementation should allow to share buffers with size of at least
+ * 512KB. Due to align issue mentioned above, we need to increase this
+ * value with one.
+ */
+#define FFA_MAX_SHM_PAGE_COUNT          (SZ_512K / FFA_PAGE_SIZE + 1)
+
+/*
+ * Limits the number of shared buffers that guest can have at once. This
+ * is to prevent case, when guests tricks XEN into exhausting its own
+ * memory by allocating many small buffers. This value has been chosen
+ * arbitrary.
+ */
+#define FFA_MAX_SHM_COUNT               32
+
+/* FF-A-1.1-REL0 section 10.9.2 Memory region handle, page 167 */
+#define FFA_HANDLE_HYP_FLAG             BIT(63, ULL)
+#define FFA_HANDLE_INVALID              0xffffffffffffffffULL
+
+/*
+ * The bits for FFA_NORMAL_MEM_REG_ATTR FFA_MEM_ACC_RW below are
+ * defined in FF-A-1.1-REL0 Table 10.18 at page 175.
+ */
+ /* Memory attributes: Normal memory, Write-Back cacheable, Inner shareable */
+#define FFA_NORMAL_MEM_REG_ATTR         0x2fU
+/* Memory access permissions: Read-write */
+#define FFA_MEM_ACC_RW                  0x2U
+
+/* FF-A-1.1-REL0 section 10.11.4 Flags usage, page 184-187 */
+/* Clear memory before mapping in receiver */
+#define FFA_MEMORY_REGION_FLAG_CLEAR            BIT(0, U)
+/* Relayer may time slice this operation */
+#define FFA_MEMORY_REGION_FLAG_TIME_SLICE       BIT(1, U)
+/* Clear memory after receiver relinquishes it */
+#define FFA_MEMORY_REGION_FLAG_CLEAR_RELINQUISH BIT(2, U)
+/* Share memory transaction */
+#define FFA_MEMORY_REGION_TRANSACTION_TYPE_SHARE (1U << 3)
+
+
 /* Framework direct request/response */
 #define FFA_MSG_FLAG_FRAMEWORK          BIT(31, U)
 #define FFA_MSG_TYPE_MASK               0xFFU;