Hi Oleksandr,
Oleksandr Tyshchenko <[email protected]> writes: > From: Oleksandr Tyshchenko <[email protected]> > > Reference-count the micro-TLBs as several bus masters can be > connected to the same micro-TLB (and drop TODO comment). > This wasn't an issue so far, since the platform devices > (this driver deals with) get assigned/deassigned together during > domain creation/destruction. But, in order to support PCI devices > (which are hot-pluggable) in the near future we will need to > take care of. > > Signed-off-by: Oleksandr Tyshchenko <[email protected]> > --- > xen/drivers/passthrough/arm/ipmmu-vmsa.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/xen/drivers/passthrough/arm/ipmmu-vmsa.c > b/xen/drivers/passthrough/arm/ipmmu-vmsa.c > index 22dd84e..32609f8 100644 > --- a/xen/drivers/passthrough/arm/ipmmu-vmsa.c > +++ b/xen/drivers/passthrough/arm/ipmmu-vmsa.c > @@ -134,6 +134,7 @@ struct ipmmu_vmsa_device { > spinlock_t lock; /* Protects ctx and domains[] */ > DECLARE_BITMAP(ctx, IPMMU_CTX_MAX); > struct ipmmu_vmsa_domain *domains[IPMMU_CTX_MAX]; > + unsigned int utlb_refcount[IPMMU_UTLB_MAX]; > const struct ipmmu_features *features; > }; > > @@ -477,13 +478,12 @@ static int ipmmu_utlb_enable(struct ipmmu_vmsa_domain > *domain, > } > } > > - /* > - * TODO: Reference-count the micro-TLB as several bus masters can be > - * connected to the same micro-TLB. > - */ > - ipmmu_imuasid_write(mmu, utlb, 0); > - ipmmu_imuctr_write(mmu, utlb, imuctr | > - IMUCTR_TTSEL_MMU(domain->context_id) | IMUCTR_MMUEN); > + if ( mmu->utlb_refcount[utlb]++ == 0 ) > + { > + ipmmu_imuasid_write(mmu, utlb, 0); > + ipmmu_imuctr_write(mmu, utlb, imuctr | > + IMUCTR_TTSEL_MMU(domain->context_id) | > IMUCTR_MMUEN); > + } > > return 0; > } > @@ -494,7 +494,8 @@ static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain > *domain, > { > struct ipmmu_vmsa_device *mmu = domain->mmu; > > - ipmmu_imuctr_write(mmu, utlb, 0); It would be great to have + ASSERT(mmu->utlb_refcount[utlb] > 0); there. Just in case. > + if ( --mmu->utlb_refcount[utlb] == 0 ) > + ipmmu_imuctr_write(mmu, utlb, 0); > } > > /* Domain/Context Management */ -- Volodymyr Babchuk at EPAM
