Re: [PATCH v4 1/4] ACPICA: actbl2.h: Add bit constants of the Flags field in the IOVT IOMMU structure

[Bibo Mao]

On 2026/11/5 下午6:31, Huacai Chen wrote:
> On Thu, Nov 5, 2026 at 5:49 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > On 2026/11/5 下午5:31, Huacai Chen wrote:
> > > On Thu, Nov 5, 2026 at 5:14 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > > > On 2026/10/23 下午3:59, Huacai Chen wrote:
> > > > > Bibo,
> > > > >
> > > > > Now I have applied this series but with some modifications, please
> > > > > double check and test the code.
> > > > >
> > > > > https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson.git/log/?h=loongarch-next
> > > > In my v4 submit, it is:
> > > > +               case ACPI_IOVT_DEVICE_ENTRY_START:
> > > > +                       is_start = true;
> > > > +                       start_devid = ep->device_id;
> > > > +                       break;
> > > > however in rc1, it is modified as:
> > > >                    case ACPI_IOVT_DEVICE_ENTRY_START:
> > > >                            is_start = true;
> > > >                            entry->start_devid = ep->device_id;
> > > >                            break;
> > > > Here entry is not allocated and NULL pointer, it is allocated in
> > > > ACPI_IOVT_DEVICE_ENTRY_END switch case.
> > > >
> > > > I really do not know what is aid to modify it and let others to test.
> > > Sorry, it's my fault.
> > >
> > > In theory I should point out the modification (eliminating the local
> > > variable start_devid) and refresh a new version. But we have no time
> > > to do this because when the first patch is merged into the ACPI repo
> > > it is near the merge window.
> > Maybe our work style is different, I do not care much for the coding style.
> > > If you agree, I will submit such modifications to fix it.
> > fix is welcome.
> > > diff --git a/drivers/acpi/loongarch/iovt.c b/drivers/acpi/loongarch/iovt.c
> > > index 87cee4f0fc80..4cdac28a1fd0 100644
> > > --- a/drivers/acpi/loongarch/iovt.c
> > > +++ b/drivers/acpi/loongarch/iovt.c
> > > @@ -115,6 +115,10 @@ static int __init iovt_add_iommu(struct
> > > acpi_iovt_iommu *iommu)
> > >           for (i = 0; i < iommu->device_entry_num; i++) {
> > >                   switch (ep->type) {
> > >                   case ACPI_IOVT_DEVICE_ENTRY_START:
> > > +                       entry = kzalloc_obj(struct iovt_device_entry,
> > > GFP_ATOMIC);
> > There will be memory leak problem if there are START/START/END in the table.
> That means a broken table? I think we don't need to consider broken
> tables, because there may be kinds of broken pattern rather than just
> a START/START/END.
yes, START/END/START, START/START/END, START/SINGLE/END. what is the 
relationship between "don't need to consider" and kinds of broken pattern?

what is the policy from your side with such BIOS table? let memory leak 
and continue?

> Huacai
>
> > Regards
> > Bibo Mao
> > > +                       if (!entry)
> > > +                               return -ENOMEM;
> > > +
> > >                           is_start = true;
> > >                           entry->start_devid = ep->device_id;
> > >                           break;
> > > @@ -122,10 +126,6 @@ static int __init iovt_add_iommu(struct
> > > acpi_iovt_iommu *iommu)
> > >                           if (!is_start)
> > >                                   break;
> > >
> > > -                       entry = kzalloc_obj(struct iovt_device_entry,
> > > GFP_ATOMIC);
> > > -                       if (!entry)
> > > -                               return -ENOMEM;
> > > -
> > >                           is_start = false;
> > >                           entry->end_devid = ep->device_id;
> > >                           list_add_tail(&entry->list, &np->ep_list);
> > >
> > > Huacai
> > >
> > > > > Huacai
> > > > >
> > > > > On Mon, Oct 12, 2026 at 3:16 PM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
> > > > > > This change is already merged in acpica tree.
> > > > > >
> > > > > > slightly ping.
> > > > > >
> > > > > > On Tue, Sep 22, 2026 at 08:10:55PM +0800, Bibo Mao wrote:
> > > > > >     > According to the IOVT specification, define macros for each bit of the
> > > > > >     > Flags field in the IOVT IOMMU structure.
> > > > > >     >
> > > > > >     > Link: https://github.com/open-acpica/acpica/commit/352f750e4cc0
> > > > > >     > Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
> > > > > >     > ---
> > > > > >     >  include/acpi/actbl2.h | 7 +++++++
> > > > > >     >  1 file changed, 7 insertions(+)
> > > > > >     >
> > > > > >     > diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
> > > > > >     > index baef525367b5..76e4a5bc79b4 100644
> > > > > >     > --- a/include/acpi/actbl2.h
> > > > > >     > +++ b/include/acpi/actbl2.h
> > > > > >     > @@ -919,6 +919,13 @@ struct acpi_iovt_iommu {
> > > > > >     >       u32 device_entry_offset;
> > > > > >     >  };
> > > > > >     >
> > > > > >     > +/* Masks for Flags field above */
> > > > > >     > +#define ACPI_IOVT_IOMMU_PCI_DEVICE           (1<<0)
> > > > > >     > +#define ACPI_IOVT_IOMMU_PXM_VALID            (1<<1)
> > > > > >     > +#define ACPI_IOVT_IOMMU_MAGAGE_BY_SEGMENT    (1<<2)
> > > > > >     > +#define ACPI_IOVT_IOMMU_HW_CAP_SUPPORT               (1<<3)
> > > > > >     > +#define ACPI_IOVT_IOMMU_MSI_INT_BYPASS               (1<<4)
> > > > > >     > +
> > > > > >     >  struct acpi_iovt_device_entry {
> > > > > >     >       u8 type;
> > > > > >     >       u8 length;
> > > > > >     > --
> > > > > >     > 2.39.3
> > > > > >     >