On 2024-03-14 09:32, Jan Beulich wrote:
On 14.03.2024 08:42, Nicola Vetrini wrote:
The 'cmd' parameter of amd_iommu_send_guest_cmd is passed
to a function that expects arrays of size 4, therefore
specifying explicitly the size also in amd_iommu_send_guest_cmd
allows not to accidentally pass a smaller array or assume that
send_iommu_command handles array sizes >4 correctly.
No functional change.
Signed-off-by: Nicola Vetrini <[email protected]>
---
All current users pass an array of size 4, hence this patch is
addressing
a potential issue noticed by the analyzer in the context of Rule 17.5
("The function argument corresponding to a parameter declared to have
an array
type shall have an appropriate number of elements"), not an actual
problem in
the sources.
While true, I think we want to consider alternatives. First one being
to rip
out this dead code (thus addressing other Misra concerns as well).
Second,
if we meant to keep it, to properly do away with the (ab)use of u32[].
I'm not understanding what you consider dead code.
I see three users of amd_iommu_send_guest_cmd and seven for
send_iommu_command.
I can adjust u32 for sure. There are also other u32/uint32_t
incosistencies in that header.
Finally, if to be taken in this least-effort shape, ...
--- a/xen/drivers/passthrough/amd/iommu.h
+++ b/xen/drivers/passthrough/amd/iommu.h
@@ -346,7 +346,7 @@ void cf_check amd_iommu_crash_shutdown(void);
/* guest iommu support */
#ifdef CONFIG_HVM
-void amd_iommu_send_guest_cmd(struct amd_iommu *iommu, u32 cmd[]);
+void amd_iommu_send_guest_cmd(struct amd_iommu *iommu, u32 cmd[4]);
... u32 here and ...
--- a/xen/drivers/passthrough/amd/iommu_cmd.c
+++ b/xen/drivers/passthrough/amd/iommu_cmd.c
@@ -390,7 +390,7 @@ void amd_iommu_flush_all_caches(struct amd_iommu
*iommu)
flush_command_buffer(iommu, 0);
}
-void amd_iommu_send_guest_cmd(struct amd_iommu *iommu, u32 cmd[])
+void amd_iommu_send_guest_cmd(struct amd_iommu *iommu, u32 cmd[4])
... here would better be replaced by uint32_t at the same time, not the
least because that's what ...
{
send_iommu_command(iommu, cmd);
... this function already takes afaics.
Jan
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)
