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.
You can find the VT-d Posted-Interrtups Spec. in the following URL:
http://www.intel.com/content/www/us/en/intelligent-systems/intel-technology/vt-directed-io-spec.html
This series was part of http://thread.gmane.org/gmane.linux.kernel.iommu/7708. To make things clear, send out IOMMU part here.
v3->v4:
* Change capability to a int variant flags instead of a function call
* Add hotplug case for VT-d PI
Feng Wu (8):
iommu: Add new member capability to struct irq_remap_ops
iommu, x86: Define new irte structure for VT-d Posted-Interrupts
iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip
iommu, x86: No need to migrating irq for VT-d Posted-Interrupts
iommu, x86: Add cap_pi_support() to detect VT-d PI capability
iommu, x86: Setup Posted-Interrupts capability for Intel iommu
iommu, x86: define irq_remapping_cap()
iommu, x86: Properly handler PI for IOMMU hotplug
arch/x86/include/asm/irq_remapping.h | 11 +++++
drivers/iommu/intel_irq_remapping.c | 78 +++++++++++++++++++++++++++++++++-
drivers/iommu/irq_remapping.c | 11 +++++
drivers/iommu/irq_remapping.h | 6 +++
include/linux/dmar.h | 32 ++++++++++++++
include/linux/intel-iommu.h | 1 +
6 files changed, 138 insertions(+), 1 deletions(-)
This patch adds a new member capability to struct irq_remap_ops,
this new function ops can be used to check whether some
features are supported, such as VT-d Posted-Interrupts.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
---
arch/x86/include/asm/irq_remapping.h | 4 ++++
drivers/iommu/irq_remapping.h | 3 +++
2 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index 6ba2431..f67ae08 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -31,6 +31,10 @@ struct irq_alloc_info;
#ifdef CONFIG_IRQ_REMAP
+enum irq_remap_cap {
+ IRQ_POSTING_CAP = 0,
+};
+
extern void setup_irq_remapping_ops(void);
extern int irq_remapping_supported(void);
extern void set_irq_remapping_broken(void);
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index 4bd791d..69b2a1c 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -36,6 +36,9 @@ extern int no_x2apic_optout;
extern int irq_remapping_enabled;
struct irq_remap_ops {
+ /* The supported capabilites */
+ int capability;
+
/* Check whether Interrupt Remapping is supported */
int (*supported)(void);
--
1.7.1
Add a new irte_pi structure for VT-d Posted-Interrupts.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
Acked-by: David Woodhouse <[email protected]>
---
include/linux/dmar.h | 32 ++++++++++++++++++++++++++++++++
1 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 8473756..c7f9cda 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -212,6 +212,38 @@ struct irte {
};
};
+struct irte_pi {
+ union {
+ struct {
+ __u64 present : 1,
+ fpd : 1,
+ __reserved_1 : 6,
+ avail : 4,
+ __reserved_2 : 2,
+ urg : 1,
+ pst : 1,
+ vector : 8,
+ __reserved_3 : 14,
+ pda_l : 26;
+ };
+ __u64 low;
+ };
+
+ union {
+ struct {
+ __u64 sid : 16,
+ sq : 2,
+ svt : 2,
+ __reserved_4 : 12,
+ pda_h : 32;
+ };
+ __u64 high;
+ };
+};
+
+#define PDA_LOW_BIT 26
+#define PDA_HIGH_BIT 32
+
enum {
IRQ_REMAP_XAPIC_MODE,
IRQ_REMAP_X2APIC_MODE,
--
1.7.1
Implement irq_set_vcpu_affinity for intel_ir_chip.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
Acked-by: David Woodhouse <[email protected]>
---
arch/x86/include/asm/irq_remapping.h | 5 ++++
drivers/iommu/intel_irq_remapping.c | 35 ++++++++++++++++++++++++++++++++++
2 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index f67ae08..f87ac70 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -60,6 +60,11 @@ static inline struct irq_domain *arch_get_ir_parent_domain(void)
return x86_vector_domain;
}
+struct vcpu_data {
+ u64 pi_desc_addr; /* Physical address of PI Descriptor */
+ u32 vector; /* Guest vector of the interrupt */
+};
+
#else /* CONFIG_IRQ_REMAP */
static inline void setup_irq_remapping_ops(void) { }
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index f6da3b2..48c2051 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -42,6 +42,7 @@ struct irq_2_iommu {
struct intel_ir_data {
struct irq_2_iommu irq_2_iommu;
struct irte irte_entry;
+ struct irte_pi irte_pi_entry;
union {
struct msi_msg msi_entry;
};
@@ -1010,10 +1011,44 @@ static void intel_ir_compose_msi_msg(struct irq_data *irq_data,
*msg = ir_data->msi_entry;
}
+static int intel_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
+{
+ struct intel_ir_data *ir_data = data->chip_data;
+ struct irte_pi *irte_pi = &ir_data->irte_pi_entry;
+ struct vcpu_data *vcpu_pi_info;
+
+ /* stop posting interrupts, back to remapping mode */
+ if (!vcpu_info)
+ modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry);
+ else {
+ vcpu_pi_info = (struct vcpu_data *)vcpu_info;
+ memcpy(irte_pi, &ir_data->irte_entry, sizeof(struct irte));
+
+ irte_pi->urg = 0;
+ irte_pi->vector = vcpu_pi_info->vector;
+ irte_pi->pda_l = (vcpu_pi_info->pi_desc_addr >>
+ (32 - PDA_LOW_BIT)) & ~(-1UL << PDA_LOW_BIT);
+ irte_pi->pda_h = (vcpu_pi_info->pi_desc_addr >> 32) &
+ ~(-1UL << PDA_HIGH_BIT);
+
+ irte_pi->__reserved_1 = 0;
+ irte_pi->__reserved_2 = 0;
+ irte_pi->__reserved_3 = 0;
+ irte_pi->__reserved_4 = 0;
+
+ irte_pi->pst = 1;
+
+ modify_irte(&ir_data->irq_2_iommu, (struct irte *)irte_pi);
+ }
+
+ return 0;
+}
+
static struct irq_chip intel_ir_chip = {
.irq_ack = ir_ack_apic_edge,
.irq_set_affinity = intel_ir_set_affinity,
.irq_compose_msi_msg = intel_ir_compose_msi_msg,
+ .irq_set_vcpu_affinity = intel_ir_set_vcpu_affinity,
};
static void intel_irq_remapping_prepare_irte(struct intel_ir_data *data,
--
1.7.1
We don't need to migrate the irqs for VT-d Posted-Interrupts here.
When 'pst' is set in IRTE, the associated irq will be posted to
guests instead of interrupt remapping. The destination of the
interrupt is set in Posted-Interrupts Descriptor, and the migration
happens during vCPU scheduling.
However, we still update the cached irte here, which can be used
when changing back to remapping mode.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
Acked-by: David Woodhouse <[email protected]>
---
drivers/iommu/intel_irq_remapping.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 48c2051..ab9057a 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -977,6 +977,7 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
{
struct intel_ir_data *ir_data = data->chip_data;
struct irte *irte = &ir_data->irte_entry;
+ struct irte_pi *irte_pi = (struct irte_pi *)irte;
struct irq_cfg *cfg = irqd_cfg(data);
struct irq_data *parent = data->parent_data;
int ret;
@@ -991,7 +992,10 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
*/
irte->vector = cfg->vector;
irte->dest_id = IRTE_DEST(cfg->dest_apicid);
- modify_irte(&ir_data->irq_2_iommu, irte);
+
+ /* We don't need to modify irte if the interrupt is for posting. */
+ if (irte_pi->pst != 1)
+ modify_irte(&ir_data->irq_2_iommu, irte);
/*
* After this point, all the interrupts will start arriving
--
1.7.1
Add helper function to detect VT-d Posted-Interrupts capability.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
Acked-by: David Woodhouse <[email protected]>
---
include/linux/intel-iommu.h | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index ecaf3a9..8174ae8 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -87,6 +87,7 @@ static inline void dmar_writeq(void __iomem *addr, u64 val)
/*
* Decoding Capability Register
*/
+#define cap_pi_support(c) (((c) >> 59) & 1)
#define cap_read_drain(c) (((c) >> 55) & 1)
#define cap_write_drain(c) (((c) >> 54) & 1)
#define cap_max_amask_val(c) (((c) >> 48) & 0x3f)
--
1.7.1
Set Posted-Interrupts capability for Intel iommu when IR is enabled,
clear it when IR is disabled.
Signed-off-by: Feng Wu <[email protected]>
---
drivers/iommu/intel_irq_remapping.c | 34 ++++++++++++++++++++++++++++++++++
drivers/iommu/irq_remapping.c | 2 ++
drivers/iommu/irq_remapping.h | 3 +++
3 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index ab9057a..130a92b 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -635,6 +635,20 @@ static int __init intel_enable_irq_remapping(void)
irq_remapping_enabled = 1;
+ /*
+ * Set Posted-Interrupts capability.
+ */
+ if (!disable_irq_post) {
+ intel_irq_remap_ops.capability |= 1 << IRQ_POSTING_CAP;
+
+ for_each_iommu(iommu, drhd)
+ if (!cap_pi_support(iommu->cap)) {
+ intel_irq_remap_ops.capability &=
+ ~(1 << IRQ_POSTING_CAP);
+ break;
+ }
+ }
+
pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
@@ -843,6 +857,12 @@ static void disable_irq_remapping(void)
iommu_disable_irq_remapping(iommu);
}
+
+ /*
+ * Clear Posted-Interrupts capability.
+ */
+ if (!disable_irq_post)
+ intel_irq_remap_ops.capability &= ~(1 << IRQ_POSTING_CAP);
}
static int reenable_irq_remapping(int eim)
@@ -870,6 +890,20 @@ static int reenable_irq_remapping(int eim)
if (!setup)
goto error;
+ /*
+ * Set Posted-Interrupts capability.
+ */
+ if (!disable_irq_post) {
+ intel_irq_remap_ops.capability |= 1 << IRQ_POSTING_CAP;
+
+ for_each_iommu(iommu, drhd)
+ if (!cap_pi_support(iommu->cap)) {
+ intel_irq_remap_ops.capability &=
+ ~(1 << IRQ_POSTING_CAP);
+ break;
+ }
+ }
+
return 0;
error:
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index 3c3da04..e63e969 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -24,6 +24,8 @@ int irq_remap_broken;
int disable_sourceid_checking;
int no_x2apic_optout;
+int disable_irq_post = 1;
+
static struct irq_remap_ops *remap_ops;
static void irq_remapping_disable_io_apic(void)
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index 69b2a1c..fe6ef36 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -35,6 +35,8 @@ extern int disable_sourceid_checking;
extern int no_x2apic_optout;
extern int irq_remapping_enabled;
+extern int disable_irq_post;
+
struct irq_remap_ops {
/* The supported capabilites */
int capability;
@@ -74,6 +76,7 @@ extern void ir_ack_apic_edge(struct irq_data *data);
#define irq_remapping_enabled 0
#define disable_irq_remap 1
#define irq_remap_broken 0
+#define disable_irq_post 1
#endif /* CONFIG_IRQ_REMAP */
--
1.7.1
This patch adds a new interface irq_remapping_cap() to detect
whether irq remapping supports new features, such as VT-d
Posted-Interrupts. We export this function out, so that KVM
code can check this and use this mechanism properly.
Signed-off-by: Feng Wu <[email protected]>
Reviewed-by: Jiang Liu <[email protected]>
---
arch/x86/include/asm/irq_remapping.h | 2 ++
drivers/iommu/irq_remapping.c | 9 +++++++++
2 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index f87ac70..b3ad067 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -37,6 +37,7 @@ enum irq_remap_cap {
extern void setup_irq_remapping_ops(void);
extern int irq_remapping_supported(void);
+extern bool irq_remapping_cap(enum irq_remap_cap cap);
extern void set_irq_remapping_broken(void);
extern int irq_remapping_prepare(void);
extern int irq_remapping_enable(void);
@@ -69,6 +70,7 @@ struct vcpu_data {
static inline void setup_irq_remapping_ops(void) { }
static inline int irq_remapping_supported(void) { return 0; }
+static bool irq_remapping_cap(enum irq_remap_cap cap) { return 0; }
static inline void set_irq_remapping_broken(void) { }
static inline int irq_remapping_prepare(void) { return -ENODEV; }
static inline int irq_remapping_enable(void) { return -ENODEV; }
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index e63e969..51c3b48 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -103,6 +103,15 @@ int irq_remapping_supported(void)
return remap_ops->supported();
}
+bool irq_remapping_cap(enum irq_remap_cap cap)
+{
+ if (!remap_ops || disable_irq_post)
+ return 0;
+
+ return (remap_ops->capability & (1 << cap));
+}
+EXPORT_SYMBOL_GPL(irq_remapping_cap);
+
int __init irq_remapping_prepare(void)
{
if (!remap_ops || !remap_ops->prepare)
--
1.7.1
Return error when inserting a new IOMMU which doesn't support PI
if PI is currently in use.
Signed-off-by: Feng Wu <[email protected]>
---
drivers/iommu/intel_irq_remapping.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 130a92b..0c2c317 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1339,6 +1339,9 @@ int dmar_ir_hotplug(struct dmar_drhd_unit *dmaru, bool insert)
return -EINVAL;
if (!ecap_ir_support(iommu->ecap))
return 0;
+ if (irq_remapping_cap(IRQ_POSTING_CAP) &&
+ !cap_pi_support(iommu->cap))
+ return -EBUSY;
if (insert) {
if (!iommu->ir_table)
--
1.7.1
> -----Original Message-----
> From: Joerg Roedel [mailto:[email protected]]
> Sent: Tuesday, March 31, 2015 11:17 PM
> To: Wu, Feng
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: Re: [v4 2/8] iommu, x86: Define new irte structure for VT-d
> Posted-Interrupts
>
> On Tue, Mar 24, 2015 at 02:32:01AM +0000, Wu, Feng wrote:
> > > I think it is better to put this as a union into struct irte. It saves
> > > memory and unnecessary casting in later patches.
> >
> > Thanks for the comments!
>
> Thinking more about this, I think its probably fine to keep the two
> versions of the irte seperate like in this patch-set. It allows to
> update the non-posted irte when the posted irte is active at the moment
> and makes the transition between both irte variants easier.
>
> But what I still don't like is the type casting necessary when calling
> modify_irte(). Can you abstract this and put the decission whether irte
> or irte_pi is set active into modify_irte? It required to change the
> interface of modify_irte, but that should be easy.
>
Sound good! Then we can keep the difference inside modify_irte().
BTW, could you please have a look at other patches in this series?
Thanks,
Feng
>
> Joerg
On Mon, Feb 02, 2015 at 04:06:56PM +0800, 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.
>
> You can find the VT-d Posted-Interrtups Spec. in the following URL:
> http://www.intel.com/content/www/us/en/intelligent-systems/intel-technology/vt-directed-io-spec.html
>
> This series was part of http://thread.gmane.org/gmane.linux.kernel.iommu/7708. To make things clear, send out IOMMU part here.
Besides the modify_irte() changes I asked for the patch-set looks good.
I just have some concerns what these changes mean for the VT-d kdump
improvements Zhen-Hua Li is working on. Can you please discuss the
implications of having both patch-sets applied with him and make sure
they work together? I think in its current form your patch-set breaks
the kdump support patches. I added Zhen-Hua to Cc.
Thanks,
Joerg
Hi Feng Wu,
In my patchset, I created a new member ir_table->base_old_phys; In the
normal kernel, everything is the same. In kdump kernel, ir_table->base
is used for a buffer, and ir_table->base_old_phys is the physical
address of the tables used by the old kernel, also being used by the
current kernel.
I did this in modify_irte():
set_64bit(&irte->high, irte_modified->high);
+
+#ifdef CONFIG_CRASH_DUMP
+ if (is_kdump_kernel())
+ __iommu_update_old_irte(iommu, index);
+#endif
__iommu_flush_cache(iommu, irte, sizeof(*irte));
Here the irte tables are stored in two places:
iommu->ir_table->base : It is a buffer in kdump kernel, which is the
running kernel;
iommu->ir_table->base_old_phys : It is the irte used by the old kernel;
And function __iommu_update_old_irte is used to save the content of
iommu->ir_table->base to iommu->ir_table->base_old_phys. Because in
kdump kernel, the vt-d is using ir_table->base_old_phys, not
ir_table->base, so we need to copy the updated ir_table->base to
ir_table->base_old_phys .
Thanks
Zhenhua
On 04/02/2015 07:28 PM, Joerg Roedel wrote:
> On Mon, Feb 02, 2015 at 04:06:56PM +0800, 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.
>>
>> You can find the VT-d Posted-Interrtups Spec. in the following URL:
>> http://www.intel.com/content/www/us/en/intelligent-systems/intel-technology/vt-directed-io-spec.html
>>
>> This series was part of http://thread.gmane.org/gmane.linux.kernel.iommu/7708. To make things clear, send out IOMMU part here.
>
> Besides the modify_irte() changes I asked for the patch-set looks good.
> I just have some concerns what these changes mean for the VT-d kdump
> improvements Zhen-Hua Li is working on. Can you please discuss the
> implications of having both patch-sets applied with him and make sure
> they work together? I think in its current form your patch-set breaks
> the kdump support patches. I added Zhen-Hua to Cc.
>
> Thanks,
>
> Joerg
>
> -----Original Message-----
> From: Li, ZhenHua [mailto:[email protected]]
> Sent: Friday, April 03, 2015 4:13 PM
> To: Wu, Feng
> Cc: Joerg Roedel; [email protected]; [email protected];
> [email protected]; [email protected]; Li, ZhenHua
> Subject: Re: [v4 0/8] Add VT-d Posted-Interrupts support - IOMMU part
>
> Hi Feng Wu,
> In my patchset, I created a new member ir_table->base_old_phys; In the
> normal kernel, everything is the same. In kdump kernel, ir_table->base
> is used for a buffer, and ir_table->base_old_phys is the physical
> address of the tables used by the old kernel, also being used by the
> current kernel.
>
> I did this in modify_irte():
>
> set_64bit(&irte->high, irte_modified->high);
> +
> +#ifdef CONFIG_CRASH_DUMP
> + if (is_kdump_kernel())
> + __iommu_update_old_irte(iommu, index);
> +#endif
> __iommu_flush_cache(iommu, irte, sizeof(*irte));
>
>
> Here the irte tables are stored in two places:
> iommu->ir_table->base : It is a buffer in kdump kernel, which is the
> running kernel;
> iommu->ir_table->base_old_phys : It is the irte used by the old kernel;
>
> And function __iommu_update_old_irte is used to save the content of
> iommu->ir_table->base to iommu->ir_table->base_old_phys. Because in
> kdump kernel, the vt-d is using ir_table->base_old_phys, not
> ir_table->base, so we need to copy the updated ir_table->base to
> ir_table->base_old_phys .
>
Hi Zhenhua,
Thanks very much for your clarification! Basically, the main purpose of my
Patch-set is to provide an interface to KVM, so that KVM can update irte
for posted-interrupts. In this interface, it calls modify_irte(). I also go
through your patch set with the associated part, seems I cannot find
any conflicts with your patches. What is your idea about this? Thanks a lot!
Thanks,
Feng
-
>
> Thanks
> Zhenhua
>
> On 04/02/2015 07:28 PM, Joerg Roedel wrote:
> > On Mon, Feb 02, 2015 at 04:06:56PM +0800, 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.
> >>
> >> You can find the VT-d Posted-Interrtups Spec. in the following URL:
> >>
> http://www.intel.com/content/www/us/en/intelligent-systems/intel-technolog
> y/vt-directed-io-spec.html
> >>
> >> This series was part of
> http://thread.gmane.org/gmane.linux.kernel.iommu/7708. To make things
> clear, send out IOMMU part here.
> >
> > Besides the modify_irte() changes I asked for the patch-set looks good.
> > I just have some concerns what these changes mean for the VT-d kdump
> > improvements Zhen-Hua Li is working on. Can you please discuss the
> > implications of having both patch-sets applied with him and make sure
> > they work together? I think in its current form your patch-set breaks
> > the kdump support patches. I added Zhen-Hua to Cc.
> >
> > Thanks,
> >
> > Joerg
> >