[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [v3 04/15] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature
> -----Original Message----- > From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx] > Sent: Thursday, June 25, 2015 5:06 PM > To: Wu, Feng; xen-devel@xxxxxxxxxxxxx > Cc: Tian, Kevin; keir@xxxxxxx; george.dunlap@xxxxxxxxxxxxx; > jbeulich@xxxxxxxx; Zhang, Yang Z > Subject: Re: [Xen-devel] [v3 04/15] iommu: Add iommu_intpost to control VT-d > Posted-Interrupts feature > > On 24/06/15 06:18, Feng Wu wrote: > > VT-d Posted-Interrupts is an enhancement to CPU side Posted-Interrupt. > > With VT-d Posted-Interrupts enabled, external interrupts from > > direct-assigned devices can be delivered to guests without VMM > > intervention when guest is running in non-root mode. > > > > This patch adds variable 'iommu_intpost' to control whether enable VT-d > > posted-interrupt or not in the generic IOMMU code. > > > > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> > > --- > > v3: > > - Remove pointless initializer for 'iommu_intpost'. > > - Some adjustment for "if no intremap then no intpost" logic. > > * For parse_iommu_param(), move it to the end of the function, > > so we don't need to add the some logic when introduing the > > new kernel parameter 'intpost' in later patch. > > * Add this logic in iommu_setup() after iommu_hardware_setup() > > is called. > > > > xen/drivers/passthrough/iommu.c | 10 +++++++++- > > xen/include/xen/iommu.h | 2 +- > > 2 files changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/xen/drivers/passthrough/iommu.c > b/xen/drivers/passthrough/iommu.c > > index 06cb38f..597f676 100644 > > --- a/xen/drivers/passthrough/iommu.c > > +++ b/xen/drivers/passthrough/iommu.c > > @@ -39,6 +39,7 @@ static void iommu_dump_p2m_table(unsigned char > key); > > * no-snoop Disable VT-d Snoop Control > > * no-qinval Disable VT-d Queued Invalidation > > * no-intremap Disable VT-d Interrupt Remapping > > + * no-intpost Disable VT-d Interrupt posting > > */ > > custom_param("iommu", parse_iommu_param); > > bool_t __initdata iommu_enable = 1; > > @@ -51,6 +52,7 @@ bool_t __read_mostly iommu_passthrough; > > bool_t __read_mostly iommu_snoop = 1; > > bool_t __read_mostly iommu_qinval = 1; > > bool_t __read_mostly iommu_intremap = 1; > > +bool_t __read_mostly iommu_intpost; > > bool_t __read_mostly iommu_hap_pt_share = 1; > > bool_t __read_mostly iommu_debug; > > bool_t __read_mostly amd_iommu_perdev_intremap = 1; > > @@ -112,6 +114,9 @@ static void __init parse_iommu_param(char *s) > > > > s = ss + 1; > > } while ( ss ); > > + > > + if ( !iommu_intremap ) > > + iommu_intpost = 0; > > This check is redundant - It will unconditionally be performed by > iommu_setup(). I would just drop the hunk. > > However, what you are missing is parsing logic to catch a command line > configuration such as "iommu=intremap,no-intpost" Doesn't the above code cover this command line? Thanks, Feng > > ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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