On 9/3/24 5:31 PM, Richard Henderson wrote:
On 9/3/24 13:16, Daniel Henrique Barboza wrote:
From: Tomasz Jeznach <tjezn...@rivosinc.com>
Extend memory transaction attributes with process identifier to allow
per-request address translation logic to use requester_id / process_id
to identify memory mapping (e.g. enabling IOMMU w/ PASID translations).
Signed-off-by: Tomasz Jeznach <tjezn...@rivosinc.com>
Reviewed-by: Frank Chang <frank.ch...@sifive.com>
Reviewed-by: Jason Chien <jason.ch...@sifive.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
---
include/exec/memattrs.h | 5 +++++
1 file changed, 5 insertions(+)
What is this for? What is different about it than requester_id?
The IOMMU memory region uses both the requester_id (internally called
device_id) and
the process id (the PASID for PCI devices) to identify a context because the
IOMMU
allows the same PID to be used by multiple requester_ids. Using only the
requester_id
is not enough to identify the IOMMU context.
Thanks,
Daniel
r~
diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
index 14cdd8d582..e27c18f3dc 100644
--- a/include/exec/memattrs.h
+++ b/include/exec/memattrs.h
@@ -52,6 +52,11 @@ typedef struct MemTxAttrs {
unsigned int memory:1;
/* Requester ID (for MSI for example) */
unsigned int requester_id:16;
+
+ /*
+ * PID (PCI PASID) support: Limited to 8 bits process identifier.
+ */
+ unsigned int pid:8;
} MemTxAttrs;
/* Bus masters which don't specify any attributes will get this,
