> -----Original Message----- > From: Thomas Gleixner [mailto:t...@linutronix.de] > Sent: Wednesday, May 20, 2015 7:46 PM > To: Wu, Feng > Cc: j...@8bytes.org; dw...@infradead.org; jiang....@linux.intel.com; > iommu@lists.linux-foundation.org; linux-ker...@vger.kernel.org > Subject: Re: [v5 3/9] iommu, x86: Abstract modify_irte() to accept two format > of irte > > On Wed, 20 May 2015, Feng Wu wrote: > > > After introducing VT-d posted-interrupts, we have two format > > of IRTE: remapped and posted. This patch make modify_irte() > > suitable for both of them. > > > static int modify_irte(struct irq_2_iommu *irq_iommu, > > - struct irte *irte_modified) > > + void *data) > > That's hardly an abstraction. You just make the pointer void so you > can hand in arbitrary nonsense. > > And with the new struct you having crap like this: > > + memcpy(irte_pi, &ir_data->irte_entry, sizeof(struct irte)); > > and this: > > + struct irte_pi *irte_pi = (struct irte_pi *)irte; > > Why not extending struct irte proper and avoid the whole void pointer > and mempcy and other crappola. > > Patch below. > > Thanks, > > tglx > > -------------> > > iommu: dmar: Extend struct irte for VT-d Posted-Interrrupts > > The IRTE (Interrupt Remapping Table Entry) is either an entry for > remapped or for posted interrupts. The hardware distiguishes between > remapped and posted entries by bit 15 in the low 64 bit of the > IRTE. If cleared the entry is remapped, if set it's posted. > > The entries have common fields and dependent on the posted bit fields > with different meanings. > > Extend struct irte to handle the differences between remap and posted > mode by having three structs in the unions: > > - Shared > - Remapped > - Posted > > Signed-off-by: Thomas Gleixner <t...@linutronix.de> > --- > include/linux/dmar.h | 68 > +++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 53 insertions(+), 15 deletions(-) > > Index: linux/include/linux/dmar.h > ================================================================ > === > --- linux.orig/include/linux/dmar.h > +++ linux/include/linux/dmar.h > @@ -185,28 +185,66 @@ static inline int dmar_device_remove(voi > > struct irte { > union { > + /* Shared between remap and posted mode*/ > struct { > - __u64 present : 1, > - fpd : 1, > - dst_mode : 1, > - redir_hint : 1, > - trigger_mode : 1, > - dlvry_mode : 3, > - avail : 4, > - __reserved_1 : 4, > - vector : 8, > - __reserved_2 : 8, > - dest_id : 32; > + __u64 present : 1, /* 0 */ > + fpd : 1, /* 1 */ > + __res0 : 6, /* 2 - 6 */ > + avail : 4, /* 8 - 11 */ > + __res1 : 3, /* 12 - 14 */ > + posted : 1, /* 15 */ > + vector : 8, /* 16 - 23 */ > + __res2 : 40; /* 24 - 63 */ > + }; > + > + /* Remap mode */ > + struct { > + __u64 r_present : 1, /* 0 */ > + r_fpd : 1, /* 1 */ > + dst_mode : 1, /* 2 */ > + redir_hint : 1, /* 3 */ > + trigger_mode : 1, /* 4 */ > + dlvry_mode : 3, /* 5 - 7 */ > + r_avail : 4, /* 8 - 11 */ > + r_res1 : 4, /* 12 - 13 */ > + r_posted : 1, /* 15 */ > + r_vector : 8, /* 16 - 23 */ > + r_res2 : 8, /* 24 - 31 */ > + dest_id : 32; /* 32 - 63 */ > + }; > + > + /* Posted mode */ > + struct { > + __u64 p_present : 1, /* 0 */ > + p_fpd : 1, /* 1 */ > + p_res0 : 6, /* 2 - 6 */ > + p_avail : 4, /* 8 - 11 */ > + p_res1 : 4, /* 12 - 13 */ > + p_urgent : 1, /* 14 */ > + p_posted : 1, /* 15 */ > + p_vector : 8, /* 16 - 23 */ > + p_res2 : 14, /* 24 - 37 */ > + pda_l : 26; /* 38 - 63 */ > }; > __u64 low; > }; > > union { > + /* Shared between remap and posted mode*/ > + struct { > + __u64 sid : 16, /* 64 - 79 */ > + sq : 2, /* 80 - 81 */ > + svt : 2, /* 82 - 83 */ > + __res3 : 44; /* 84 - 127 */ > + }; > + > + /* Posted mode*/ > struct { > - __u64 sid : 16, > - sq : 2, > - svt : 2, > - __reserved_3 : 44; > + __u64 p_sid : 16, /* 64 - 79 */ > + p_sq : 2, /* 80 - 81 */ > + p_svt : 2, /* 82 - 83 */ > + p_res3 : 12, /* 84 - 95 */ > + pda_h : 32; /* 96 - 127 */ > }; > __u64 high; > };
This looks great, thanks for your suggestion! In fact, I also thought about combining this two formats into one structure, but I encountered two problems: 1. Need change the current remapping code which uses this structure. 2. Building errors. You patch solves the first issue by generating a shared part in the union, and based on that it is easy to address the build error issue by renaming the members. Thanks, Feng _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
