[v10 00/10] Add VT-d Posted-Interrupts support - IOMMU part

[v10 00/10] Add VT-d Posted-Interrupts support - IOMMU part

[Feng Wu]

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.

This patch-set is based on the lastest x86/apic branch of tip tree.

Divide the whole series which contain multiple components into three parts:
- Prerequisite changes to irq subsystem (already merged in tip tree x86/apic branch)
- IOMMU part (in this series)
- KVM and VFIO parts (will send out this part once the first two parts are accepted)

v9->v10:
* Fix the build error found by the 0-day test infrastructure.
  - Define 'enum irq_remap_cap' outside '#ifdef CONFIG_IRQ_REMAP',
    so we can use it for the paramenter of the dummy function
    irq_remapping_cap() when CONFIG_IRQ_REMAP is not defined.
  - Make function irq_remapping_cap() inline when CONFIG_IRQ_REMAP
    is not defined.

v8->v9:
* Remove member "irte_pi_entry" in struct intel_ir_data.
* Some changes to the comments.

v7->v8:
* Save the irq mode (posted or remapped) of an IRTE in struct irq_2_iommu.
* Use this new mode to decide whether update the hardware when
modifying irte in intel_ir_set_affinity().

v6->v7:
* Add an static inline helper function set_irq_posting_cap() to set
the PI capability.
* Add some comments for the new member "ir_data->irte_pi_entry".

v5->v6:
* Extend 'struct irte' for VT-d Posted-Interrupts, combine remapped
and posted mode into one irte structure.

v4->v5:
* Abstract modify_irte() to accept two format of irte.

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: Implement irq_set_vcpu_affinity for intel_ir_chip
  iommu, x86: Save the mode (posted or remapped) of an IRTE
  iommu, x86: Avoid migrating 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: Provide irq_remapping_cap() interface
  iommu, x86: Properly handle posted interrupts for IOMMU hotplug

Thomas Gleixner (2):
  iommu: dmar: Extend struct irte for VT-d Posted-Interrupts
  iommu: dmar: Provide helper to copy shared irte fields

 arch/x86/include/asm/irq_remapping.h | 11 +++++
 drivers/iommu/intel_irq_remapping.c  | 85 +++++++++++++++++++++++++++++++++++-
 drivers/iommu/irq_remapping.c        | 11 +++++
 drivers/iommu/irq_remapping.h        |  6 +++
 include/linux/dmar.h                 | 82 +++++++++++++++++++++++++++-------
 include/linux/intel-iommu.h          |  1 +
 6 files changed, 180 insertions(+), 16 deletions(-)

-- 
2.1.0

[v10 01/10] iommu: Add new member capability to struct irq_remap_ops

[Feng Wu]

Add a new member 'capability' to struct irq_remap_ops for storing
information about available capabilities such as VT-d
Posted-Interrupts.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 arch/x86/include/asm/irq_remapping.h | 4 ++++
 drivers/iommu/irq_remapping.h        | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index 78974fb..8b432dd 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -29,6 +29,10 @@
 struct msi_msg;
 struct irq_alloc_info;
 
+enum irq_remap_cap {
+	IRQ_POSTING_CAP = 0,
+};
+
 #ifdef CONFIG_IRQ_REMAP
 
 extern void set_irq_remapping_broken(void);
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index 91d5a11..b6ca30d 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -35,6 +35,9 @@ extern int no_x2apic_optout;
 extern int irq_remapping_enabled;
 
 struct irq_remap_ops {
+	/* The supported capabilities */
+	int capability;
+
 	/* Initializes hardware and makes it ready for remapping interrupts */
 	int  (*prepare)(void);
 
-- 
2.1.0

[v10 02/10] iommu: dmar: Extend struct irte for VT-d Posted-Interrupts

[Feng Wu]

From: Thomas Gleixner <tglx@linutronix.de>

The IRTE (Interrupt Remapping Table Entry) is either an entry for
remapped or for posted interrupts. The hardware distiguishes between
remapped and posted entries by bit 15 in the low 64 bit of the
IRTE. If cleared the entry is remapped, if set it's posted.

The entries have common fields and dependent on the posted bit fields
with different meanings.

Extend struct irte to handle the differences between remap and posted
mode by having three structs in the unions:

        - Shared
        - Remapped
        - Posted

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>
---
 include/linux/dmar.h | 70 +++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 55 insertions(+), 15 deletions(-)

diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 8473756..0dbcabc 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -185,33 +185,73 @@ static inline int dmar_device_remove(void *handle)
 
 struct irte {
 	union {
+		/* Shared between remapped and posted mode*/
 		struct {
-			__u64	present 	: 1,
-				fpd		: 1,
-				dst_mode	: 1,
-				redir_hint	: 1,
-				trigger_mode	: 1,
-				dlvry_mode	: 3,
-				avail		: 4,
-				__reserved_1	: 4,
-				vector		: 8,
-				__reserved_2	: 8,
-				dest_id		: 32;
+			__u64	present		: 1,  /*  0      */
+				fpd		: 1,  /*  1      */
+				__res0		: 6,  /*  2 -  6 */
+				avail		: 4,  /*  8 - 11 */
+				__res1		: 3,  /* 12 - 14 */
+				pst		: 1,  /* 15      */
+				vector		: 8,  /* 16 - 23 */
+				__res2		: 40; /* 24 - 63 */
+		};
+
+		/* Remapped mode */
+		struct {
+			__u64	r_present	: 1,  /*  0      */
+				r_fpd		: 1,  /*  1      */
+				dst_mode	: 1,  /*  2      */
+				redir_hint	: 1,  /*  3      */
+				trigger_mode	: 1,  /*  4      */
+				dlvry_mode	: 3,  /*  5 -  7 */
+				r_avail		: 4,  /*  8 - 11 */
+				r_res0		: 4,  /* 12 - 15 */
+				r_vector	: 8,  /* 16 - 23 */
+				r_res1		: 8,  /* 24 - 31 */
+				dest_id		: 32; /* 32 - 63 */
+		};
+
+		/* Posted mode */
+		struct {
+			__u64	p_present	: 1,  /*  0      */
+				p_fpd		: 1,  /*  1      */
+				p_res0		: 6,  /*  2 -  7 */
+				p_avail		: 4,  /*  8 - 11 */
+				p_res1		: 2,  /* 12 - 13 */
+				p_urgent	: 1,  /* 14      */
+				p_pst		: 1,  /* 15      */
+				p_vector	: 8,  /* 16 - 23 */
+				p_res2		: 14, /* 24 - 37 */
+				pda_l		: 26; /* 38 - 63 */
 		};
 		__u64 low;
 	};
 
 	union {
+		/* Shared between remapped and posted mode*/
 		struct {
-			__u64	sid		: 16,
-				sq		: 2,
-				svt		: 2,
-				__reserved_3	: 44;
+			__u64	sid		: 16,  /* 64 - 79  */
+				sq		: 2,   /* 80 - 81  */
+				svt		: 2,   /* 82 - 83  */
+				__res3		: 44;  /* 84 - 127 */
+		};
+
+		/* Posted mode*/
+		struct {
+			__u64	p_sid		: 16,  /* 64 - 79  */
+				p_sq		: 2,   /* 80 - 81  */
+				p_svt		: 2,   /* 82 - 83  */
+				p_res3		: 12,  /* 84 - 95  */
+				pda_h		: 32;  /* 96 - 127 */
 		};
 		__u64 high;
 	};
 };
 
+#define PDA_LOW_BIT    26
+#define PDA_HIGH_BIT   32
+
 enum {
 	IRQ_REMAP_XAPIC_MODE,
 	IRQ_REMAP_X2APIC_MODE,
-- 
2.1.0

[v10 03/10] iommu: dmar: Provide helper to copy shared irte fields

[Feng Wu]

From: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>

Instead of open coding, provide a helper function to copy the shared
irte fields.

Signed-off-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
---
 include/linux/dmar.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 0dbcabc..e9bc929 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -249,6 +249,18 @@ struct irte {
 	};
 };
 
+static inline void dmar_copy_shared_irte(struct irte *dst, struct irte *src)
+{
+	dst->present	= src->present;
+	dst->fpd	= src->fpd;
+	dst->avail	= src->avail;
+	dst->pst	= src->pst;
+	dst->vector	= src->vector;
+	dst->sid	= src->sid;
+	dst->sq		= src->sq;
+	dst->svt	= src->svt;
+}
+
 #define PDA_LOW_BIT    26
 #define PDA_HIGH_BIT   32
 
-- 
2.1.0

[v10 04/10] iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip

[Feng Wu]

Interrupt chip callback to set the VCPU affinity for posted interrupts.

[ tglx: Use the helper function to copy from the remap irte instead of
        open coding it. Massage the comment as well ]

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/include/asm/irq_remapping.h |  5 +++++
 drivers/iommu/intel_irq_remapping.c  | 37 ++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index 8b432dd..e479fbd 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -57,6 +57,11 @@ 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 set_irq_remapping_broken(void) { }
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 8fad71c..a643eec 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1013,10 +1013,47 @@ 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 *info)
+{
+	struct intel_ir_data *ir_data = data->chip_data;
+	struct vcpu_data *vcpu_pi_info = info;
+
+	/* stop posting interrupts, back to remapping mode */
+	if (!vcpu_pi_info) {
+		modify_irte(&ir_data->irq_2_iommu, &ir_data->irte_entry);
+	} else {
+		struct irte irte_pi;
+
+		/*
+		 * We are not caching the posted interrupt entry. We
+		 * copy the data from the remapped entry and modify
+		 * the fields which are relevant for posted mode. The
+		 * cached remapped entry is used for switching back to
+		 * remapped mode.
+		 */
+		memset(&irte_pi, 0, sizeof(irte_pi));
+		dmar_copy_shared_irte(&irte_pi, &ir_data->irte_entry);
+
+		/* Update the posted mode fields */
+		irte_pi.p_pst = 1;
+		irte_pi.p_urgent = 0;
+		irte_pi.p_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);
+
+		modify_irte(&ir_data->irq_2_iommu, &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,
-- 
2.1.0

[v10 05/10] iommu, x86: Save the mode (posted or remapped) of an IRTE

[Feng Wu]

Add a new field to struct irq_2_iommu, which captures whether the
associated IRTE is in posted mode or remapped mode. We update this
field when the IRTE is written into the table.

Suggested-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/intel_irq_remapping.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index a643eec..68bce0a 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -18,6 +18,11 @@
 
 #include "irq_remapping.h"
 
+enum irq_mode {
+	IRQ_REMAPPING,
+	IRQ_POSTING,
+};
+
 struct ioapic_scope {
 	struct intel_iommu *iommu;
 	unsigned int id;
@@ -37,6 +42,7 @@ struct irq_2_iommu {
 	u16 irte_index;
 	u16 sub_handle;
 	u8  irte_mask;
+	enum irq_mode mode;
 };
 
 struct intel_ir_data {
@@ -104,6 +110,7 @@ static int alloc_irte(struct intel_iommu *iommu, int irq,
 		irq_iommu->irte_index =  index;
 		irq_iommu->sub_handle = 0;
 		irq_iommu->irte_mask = mask;
+		irq_iommu->mode = IRQ_REMAPPING;
 	}
 	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 
@@ -144,6 +151,9 @@ static int modify_irte(struct irq_2_iommu *irq_iommu,
 	__iommu_flush_cache(iommu, irte, sizeof(*irte));
 
 	rc = qi_flush_iec(iommu, index, 0);
+
+	/* Update iommu mode according to the IRTE mode */
+	irq_iommu->mode = irte->pst ? IRQ_POSTING : IRQ_REMAPPING;
 	raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 
 	return rc;
-- 
2.1.0

[v10 06/10] iommu, x86: Avoid migrating VT-d posted interrupts

[Feng Wu]

When the interrupt is configured in posted mode, the destination of
the interrupt is set in the Posted-Interrupts Descriptor and the
migration of these interrupts happens during vCPU scheduling.

We still update the cached irte, which will be used when changing back
to remapping mode, but we avoid writing the table entry.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Acked-by: David Woodhouse <David.Woodhouse-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/intel_irq_remapping.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 68bce0a..3bcb459 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1003,7 +1003,10 @@ 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);
+
+	/* Update the hardware only if the interrupt is in remapped mode. */
+	if (ir_data->irq_2_iommu.mode == IRQ_REMAPPING)
+		modify_irte(&ir_data->irq_2_iommu, irte);
 
 	/*
 	 * After this point, all the interrupts will start arriving
-- 
2.1.0

[v10 07/10] iommu, x86: Add cap_pi_support() to detect VT-d PI capability

[Feng Wu]

Add helper function to detect VT-d Posted-Interrupts capability.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Acked-by: David Woodhouse <David.Woodhouse-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 include/linux/intel-iommu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 0af9b03..0c251be 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)
-- 
2.1.0

[v10 08/10] iommu, x86: Setup Posted-Interrupts capability for Intel iommu

[Feng Wu]

Set Posted-Interrupts capability for Intel iommu when Interrupt
Remapping is enabled, clear it when disabled.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/intel_irq_remapping.c | 30 ++++++++++++++++++++++++++++++
 drivers/iommu/irq_remapping.c       |  2 ++
 drivers/iommu/irq_remapping.h       |  3 +++
 3 files changed, 35 insertions(+)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 3bcb459..0f57af7 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -581,6 +581,26 @@ error:
 	return -ENODEV;
 }
 
+/*
+ * Set Posted-Interrupts capability.
+ */
+static inline void set_irq_posting_cap(void)
+{
+	struct dmar_drhd_unit *drhd;
+	struct intel_iommu *iommu;
+
+	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;
+			}
+	}
+}
+
 static int __init intel_enable_irq_remapping(void)
 {
 	struct dmar_drhd_unit *drhd;
@@ -656,6 +676,8 @@ static int __init intel_enable_irq_remapping(void)
 
 	irq_remapping_enabled = 1;
 
+	set_irq_posting_cap();
+
 	pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
 
 	return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
@@ -856,6 +878,12 @@ 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)
@@ -883,6 +911,8 @@ static int reenable_irq_remapping(int eim)
 	if (!setup)
 		goto error;
 
+	set_irq_posting_cap();
+
 	return 0;
 
 error:
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index fc78b0d..ed605a9 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -22,6 +22,8 @@ int irq_remap_broken;
 int disable_sourceid_checking;
 int no_x2apic_optout;
 
+int disable_irq_post = 1;
+
 static int disable_irq_remap;
 static struct irq_remap_ops *remap_ops;
 
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index b6ca30d..039c7af 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -34,6 +34,8 @@ 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 capabilities */
 	int capability;
@@ -69,6 +71,7 @@ extern void ir_ack_apic_edge(struct irq_data *data);
 
 #define irq_remapping_enabled 0
 #define irq_remap_broken      0
+#define disable_irq_post      1
 
 #endif /* CONFIG_IRQ_REMAP */
 
-- 
2.1.0

[v10 09/10] iommu, x86: Provide irq_remapping_cap() interface

[Feng Wu]

Add a new interface irq_remapping_cap() to detect whether irq
remapping supports new features, such as VT-d Posted-Interrupts.

Export the function, so that KVM code can check this and use this
mechanism properly.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 arch/x86/include/asm/irq_remapping.h | 2 ++
 drivers/iommu/irq_remapping.c        | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index e479fbd..046c7fb 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -35,6 +35,7 @@ enum irq_remap_cap {
 
 #ifdef CONFIG_IRQ_REMAP
 
+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);
@@ -64,6 +65,7 @@ struct vcpu_data {
 
 #else  /* CONFIG_IRQ_REMAP */
 
+static inline 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 ed605a9..2d99930 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -81,6 +81,15 @@ void set_irq_remapping_broken(void)
 	irq_remap_broken = 1;
 }
 
+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 (disable_irq_remap)
-- 
2.1.0

[v10 10/10] iommu, x86: Properly handle posted interrupts for IOMMU hotplug

[Feng Wu]

Return error when inserting a new IOMMU which doesn't support posted
interrupts if posted interrupts are already enabled.

Signed-off-by: Feng Wu <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Acked-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/intel_irq_remapping.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 0f57af7..80f1d14 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1355,6 +1355,9 @@ 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)
-- 
2.1.0