Re: [PATCH v8 01/10] iommu/vt-d: Update iommu_attach_domain() and its callers

[Joerg Roedel]

On Mon, Jan 12, 2015 at 03:06:19PM +0800, Li, Zhen-Hua wrote:
 Allow specification of the domain-id for the new domain.
 This patch only adds the 'did' parameter to iommu_attach_domain()
 and modifies all of its callers to specify the default value of -1
 which says no did specified, allocate a new one.

I think its better to keep the old iommu_attach_domain() interface in
place and introduce a new function (like iommu_attach_domain_with_id()
or something) which has the additional parameter. Then you can rewrite
iommu_attach_domain():

iommu_attach_domai(...)
{
return iommu_attach_domain_with_id(..., -1);
}

This way you don't have to update all the callers of
iommu_attach_domain() and the interface is more readable.


Joerg

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Re: [PATCH v8 01/10] iommu/vt-d: Update iommu_attach_domain() and its callers

[Li, ZhenHua]

On 01/12/2015 11:18 PM, Joerg Roedel wrote:

On Mon, Jan 12, 2015 at 03:06:19PM +0800, Li, Zhen-Hua wrote:

Allow specification of the domain-id for the new domain.
This patch only adds the 'did' parameter to iommu_attach_domain()
and modifies all of its callers to specify the default value of -1
which says no did specified, allocate a new one.


I think its better to keep the old iommu_attach_domain() interface in
place and introduce a new function (like iommu_attach_domain_with_id()
or something) which has the additional parameter. Then you can rewrite
iommu_attach_domain():

iommu_attach_domai(...)
{
return iommu_attach_domain_with_id(..., -1);
}

This way you don't have to update all the callers of
iommu_attach_domain() and the interface is more readable.


Joerg



That's a good way. I will do this in next version.

Thanks
Zhenhua


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[PATCH v8 01/10] iommu/vt-d: Update iommu_attach_domain() and its callers

[Li, Zhen-Hua]

Allow specification of the domain-id for the new domain.
This patch only adds the 'did' parameter to iommu_attach_domain()
and modifies all of its callers to specify the default value of -1
which says no did specified, allocate a new one.

This is no functional change from current behaviour -- just enables
a functional change to be made in a later patch.

Bill Sumner:
Original version.

Li, Zhenhua:
Minor change, add change to function __iommu_attach_domain.

Signed-off-by: Bill Sumner billsumnerli...@gmail.com
Signed-off-by: Li, Zhen-Hua zhen-h...@hp.com
---
 drivers/iommu/intel-iommu.c | 34 --
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 40dfbc0..8d5c400 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1534,31 +1534,36 @@ static struct dmar_domain *alloc_domain(int flags)
 }
 
 static int __iommu_attach_domain(struct dmar_domain *domain,
-struct intel_iommu *iommu)
+struct intel_iommu *iommu,
+int domain_number)
 {
int num;
unsigned long ndomains;
 
ndomains = cap_ndoms(iommu-cap);
-   num = find_first_zero_bit(iommu-domain_ids, ndomains);
-   if (num  ndomains) {
-   set_bit(num, iommu-domain_ids);
-   iommu-domains[num] = domain;
-   } else {
-   num = -ENOSPC;
-   }
+   if (domain_number  0) {
+   num = find_first_zero_bit(iommu-domain_ids, ndomains);
+   if (num  ndomains) {
+   set_bit(num, iommu-domain_ids);
+   iommu-domains[num] = domain;
+   } else {
+   num = -ENOSPC;
+   }
+   } else
+   num = domain_number;
 
return num;
 }
 
 static int iommu_attach_domain(struct dmar_domain *domain,
-  struct intel_iommu *iommu)
+  struct intel_iommu *iommu,
+  int domain_number)
 {
int num;
unsigned long flags;
 
spin_lock_irqsave(iommu-lock, flags);
-   num = __iommu_attach_domain(domain, iommu);
+   num = __iommu_attach_domain(domain, iommu, domain_number);
spin_unlock_irqrestore(iommu-lock, flags);
if (num  0)
pr_err(IOMMU: no free domain ids\n);
@@ -1577,7 +1582,7 @@ static int iommu_attach_vm_domain(struct dmar_domain 
*domain,
if (iommu-domains[num] == domain)
return num;
 
-   return __iommu_attach_domain(domain, iommu);
+   return __iommu_attach_domain(domain, iommu, -1);
 }
 
 static void iommu_detach_domain(struct dmar_domain *domain,
@@ -2231,6 +2236,7 @@ static struct dmar_domain *get_domain_for_dev(struct 
device *dev, int gaw)
u16 dma_alias;
unsigned long flags;
u8 bus, devfn;
+   int did = -1;   /* Default to no domain_id supplied */
 
domain = find_domain(dev);
if (domain)
@@ -2264,7 +2270,7 @@ static struct dmar_domain *get_domain_for_dev(struct 
device *dev, int gaw)
domain = alloc_domain(0);
if (!domain)
return NULL;
-   domain-id = iommu_attach_domain(domain, iommu);
+   domain-id = iommu_attach_domain(domain, iommu, did);
if (domain-id  0) {
free_domain_mem(domain);
return NULL;
@@ -2442,7 +2448,7 @@ static int __init si_domain_init(int hw)
return -EFAULT;
 
for_each_active_iommu(iommu, drhd) {
-   ret = iommu_attach_domain(si_domain, iommu);
+   ret = iommu_attach_domain(si_domain, iommu, -1);
if (ret  0) {
domain_exit(si_domain);
return -EFAULT;
@@ -3866,7 +3872,7 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
iommu_enable_translation(iommu);
 
if (si_domain) {
-   ret = iommu_attach_domain(si_domain, iommu);
+   ret = iommu_attach_domain(si_domain, iommu, -1);
if (ret  0 || si_domain-id != ret)
goto disable_iommu;
domain_attach_iommu(si_domain, iommu);
-- 
2.0.0-rc0

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