Hey Lu, > On 5 Mar 2019, at 06:46, Lu Baolu <baolu...@linux.intel.com> wrote: > > Hi, > > On 3/4/19 11:46 PM, James Sewart wrote: >> Allowing IOMMU_DOMAIN_DMA type IOMMU domain to be allocated allows the >> default_domain of an iommu_group to be set. This delegates device-domain >> relationships to the generic IOMMU code. >> Signed-off-by: James Sewart <jamessew...@arista.com> >> --- >> drivers/iommu/intel-iommu.c | 113 +++++++++++++++++++++++++++--------- >> 1 file changed, 84 insertions(+), 29 deletions(-) >> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c >> index 8e0a4e2ff77f..71cd6bbfec05 100644 >> --- a/drivers/iommu/intel-iommu.c >> +++ b/drivers/iommu/intel-iommu.c >> @@ -309,6 +309,14 @@ static int hw_pass_through = 1; >> /* si_domain contains mulitple devices */ >> #define DOMAIN_FLAG_STATIC_IDENTITY (1 << 1) >> +/* Domain managed externally, don't cleanup if it isn't attached >> + * to any devices. */ >> +#define DOMAIN_FLAG_MANAGED_EXTERNALLY (1 << 2) >> + >> +/* Set after domain initialisation. Used when allocating dma domains to >> + * defer domain initialisation until it is attached to a device */ >> +#define DOMAIN_FLAG_INITIALISED (1 << 4) > > Why do you skip bit 3?
This was an oversight, I will update to use bit 3. > >> + >> #define for_each_domain_iommu(idx, domain) \ >> for (idx = 0; idx < g_num_of_iommus; idx++) \ >> if (domain->iommu_refcnt[idx]) >> @@ -558,6 +566,16 @@ static inline int domain_type_is_vm_or_si(struct >> dmar_domain *domain) >> DOMAIN_FLAG_STATIC_IDENTITY); >> } >> +static inline int domain_managed_externally(struct dmar_domain *domain) >> +{ >> + return domain->flags & DOMAIN_FLAG_MANAGED_EXTERNALLY; >> +} >> + >> +static inline int domain_is_initialised(struct dmar_domain *domain) >> +{ >> + return domain->flags & DOMAIN_FLAG_INITIALISED; >> +} >> + >> static inline int domain_pfn_supported(struct dmar_domain *domain, >> unsigned long pfn) >> { >> @@ -1662,7 +1680,7 @@ static void disable_dmar_iommu(struct intel_iommu >> *iommu) >> __dmar_remove_one_dev_info(info); >> - if (!domain_type_is_vm_or_si(domain)) { >> + if (!domain_managed_externally(domain)) { >> /* >> * The domain_exit() function can't be called under >> * device_domain_lock, as it takes this lock itself. >> @@ -1895,6 +1913,7 @@ static int domain_init(struct dmar_domain *domain, >> struct intel_iommu *iommu, >> domain->pgd = (struct dma_pte *)alloc_pgtable_page(domain->nid); >> if (!domain->pgd) >> return -ENOMEM; >> + domain->flags |= DOMAIN_FLAG_INITIALISED; >> __iommu_flush_cache(iommu, domain->pgd, PAGE_SIZE); >> return 0; >> } >> @@ -2807,14 +2826,10 @@ static inline void iommu_prepare_isa(void) >> static int md_domain_init(struct dmar_domain *domain, int guest_width); >> -static int __init si_domain_init(int hw) >> +static int __init si_domain_init(struct dmar_domain *si_domain, int hw) >> { >> int nid, ret = 0; >> - si_domain = alloc_domain(DOMAIN_FLAG_STATIC_IDENTITY); >> - if (!si_domain) >> - return -EFAULT; >> - >> if (md_domain_init(si_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) { >> domain_exit(si_domain); >> return -EFAULT; >> @@ -3417,9 +3432,16 @@ static int __init init_dmars(void) >> check_tylersburg_isoch(); >> if (iommu_identity_mapping) { >> - ret = si_domain_init(hw_pass_through); >> - if (ret) >> + si_domain = alloc_domain(DOMAIN_FLAG_STATIC_IDENTITY); > > Where will this si_domain be used? We still need to keep the global > si_domain? I am unsure of the best thing to do here. The si_domain can be initialised as a hardware passthrough which means it doesn’t have any mappings applied. I think any user allocating a domain here will always want a software passthrough domain. I’m not sure if/how to consolidate these two. > >> + if (!si_domain) { >> + ret = -EFAULT; >> goto free_iommu; >> + } >> + ret = si_domain_init(si_domain, hw_pass_through); >> + if (ret) { >> + domain_exit(si_domain); >> + goto free_iommu; >> + } >> } >> @@ -4575,7 +4597,7 @@ static int device_notifier(struct notifier_block >> *nb, >> return 0; >> dmar_remove_one_dev_info(domain, dev); >> - if (!domain_type_is_vm_or_si(domain) && list_empty(&domain->devices)) >> + if (!domain_managed_externally(domain) && list_empty(&domain->devices)) >> domain_exit(domain); >> return 0; >> @@ -5020,6 +5042,7 @@ static int md_domain_init(struct dmar_domain *domain, >> int guest_width) >> domain->pgd = (struct dma_pte *)alloc_pgtable_page(domain->nid); >> if (!domain->pgd) >> return -ENOMEM; >> + domain->flags |= DOMAIN_FLAG_INITIALISED; >> domain_flush_cache(domain, domain->pgd, PAGE_SIZE); >> return 0; >> } >> @@ -5028,28 +5051,54 @@ static struct iommu_domain >> *intel_iommu_domain_alloc(unsigned type) >> { >> struct dmar_domain *dmar_domain; >> struct iommu_domain *domain; >> + int flags = DOMAIN_FLAG_MANAGED_EXTERNALLY; >> - if (type != IOMMU_DOMAIN_UNMANAGED) >> - return NULL; >> - >> - dmar_domain = alloc_domain(DOMAIN_FLAG_VIRTUAL_MACHINE); >> - if (!dmar_domain) { >> - pr_err("Can't allocate dmar_domain\n"); >> - return NULL; >> - } >> - if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) { >> - pr_err("Domain initialization failed\n"); >> - domain_exit(dmar_domain); >> + switch (type) { >> + case IOMMU_DOMAIN_UNMANAGED: >> + flags |= DOMAIN_FLAG_VIRTUAL_MACHINE | DOMAIN_FLAG_INITIALISED; >> + dmar_domain = alloc_domain(flags); >> + if (!dmar_domain) { >> + pr_err("Can't allocate dmar_domain\n"); >> + return NULL; >> + } >> + if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) { >> + pr_err("Domain initialization failed\n"); >> + domain_exit(dmar_domain); >> + return NULL; >> + } >> + domain_update_iommu_cap(dmar_domain); >> + domain = &dmar_domain->domain; >> + domain->geometry.aperture_start = 0; >> + domain->geometry.aperture_end = >> __DOMAIN_MAX_ADDR(dmar_domain->gaw); >> + domain->geometry.force_aperture = true; >> + break; >> + case IOMMU_DOMAIN_DMA: >> + dmar_domain = alloc_domain(flags); >> + if (!dmar_domain) { >> + pr_err("Can't allocate dmar_domain\n"); > > Not necessary for memory allocation failure. I’ll update in the next revision > >> + return NULL; >> + } >> + // init domain in device attach when we know IOMMU capabilities > > Use /* */ for comments, please. I’ll update in the next revision > >> + break; >> + case IOMMU_DOMAIN_IDENTITY: >> + flags |= DOMAIN_FLAG_STATIC_IDENTITY | DOMAIN_FLAG_INITIALISED; >> + dmar_domain = alloc_domain(flags); >> + if (!dmar_domain) { >> + pr_err("Can't allocate dmar_domain\n"); >> + return NULL; >> + } >> + if (si_domain_init(dmar_domain, 0)) { >> + pr_err("Domain initialization failed\n"); >> + domain_exit(dmar_domain); >> + return NULL; >> + } >> + break; > > How about moving si domain allocation into a separated patch? There are > two significant changes here, so it worth a new patch for discussion. > > 1) a shared single si domain vs. per group si domain; > 2) previously vt-d drivers determines what kind of devices should use > identity domain; Now, it turns to iommu generic layer, behavior will > be changed. I’ll move it into another patch. Do you think the global si_domain should be returned here? >> + default: >> return NULL; >> } >> - domain_update_iommu_cap(dmar_domain); >> - >> - domain = &dmar_domain->domain; >> - domain->geometry.aperture_start = 0; >> - domain->geometry.aperture_end = __DOMAIN_MAX_ADDR(dmar_domain->gaw); >> - domain->geometry.force_aperture = true; >> - return domain; >> + dmar_domain->domain.type = type; > > Is it necessary to set this? It isn’t I’ll remove this for the next revision. > >> + return &dmar_domain->domain; >> } >> static void intel_iommu_domain_free(struct iommu_domain *domain) >> @@ -5080,8 +5129,8 @@ static int intel_iommu_attach_device(struct >> iommu_domain *domain, >> dmar_remove_one_dev_info(old_domain, dev); >> rcu_read_unlock(); >> - if (!domain_type_is_vm_or_si(old_domain) && >> - list_empty(&old_domain->devices)) >> + if (list_empty(&old_domain->devices) && >> + !domain_managed_externally(old_domain)) >> domain_exit(old_domain); >> } >> } >> @@ -5090,6 +5139,12 @@ static int intel_iommu_attach_device(struct >> iommu_domain *domain, >> if (!iommu) >> return -ENODEV; >> + // Initialise domain with IOMMU capabilities if it isn't already >> initialised > > Ditto. > >> + if (!domain_is_initialised(dmar_domain)) { >> + if (domain_init(dmar_domain, iommu, >> DEFAULT_DOMAIN_ADDRESS_WIDTH)) >> + return -ENOMEM; >> + } > > Each domain, not matter the DMA domain or UNMANAGED domain, is allocated > first and then gets initialized during device attaching, right? If so, > why do we need to have a special DOMAIN_FLAG_INITIALISED flag for DMA > domains? Only the DMA domain is initialised on attach, UNMANAGED and IDENTITY initialises with the lowest common denominator of the parameters of all attached IOMMUs using domain_update_iommu_cap. > >> + >> /* check if this iommu agaw is sufficient for max mapped address */ >> addr_width = agaw_to_width(iommu->agaw); >> if (addr_width > cap_mgaw(iommu->cap)) > > Best regards, > Lu Baolu Cheers, James.