[PATCH 0/2] iommu/amd: Fixes for x2APIC support

[PATCH 0/2] iommu/amd: Fixes for x2APIC support

[Suravee Suthikulpanit]

Adding feature support check for MMIO access to MSI capability
block registers when enabling x2APIC (XT) mode. Also fix up logic
for checking XT feature support for IVHD type 10h.

Suravee Suthikulpanit (2):
  iommu/amd: Check feature support bit before accessing MSI capability
    registers
  iommu/amd: Only support x2APIC with IVHD type 11h/40h

 drivers/iommu/amd_iommu_init.c  | 19 ++++++++++++-------
 drivers/iommu/amd_iommu_types.h |  2 +-
 2 files changed, 13 insertions(+), 8 deletions(-)

-- 
1.8.3.1

[PATCH 1/2] iommu/amd: Check feature support bit before accessing MSI capability registers

[Suravee Suthikulpanit]

The IOMMU MMIO access to MSI capability registers is available only if
the EFR[MsiCapMmioSup] is set. Current implementation assumes this bit
is set if the EFR[XtSup] is set, which might not be the case.

Fix by checking the EFR[MsiCapMmioSup] before accessing the MSI address
low/high and MSI data registers via the MMIO.

Fixes: 66929812955b ('iommu/amd: Add support for X2APIC IOMMU interrupts')
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd_iommu_init.c  | 17 ++++++++++++-----
 drivers/iommu/amd_iommu_types.h |  1 +
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 4413aa6..1dcc0b3 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -146,7 +146,7 @@ struct ivmd_header {
 bool amd_iommu_irq_remap __read_mostly;
 
 int amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_VAPIC;
-static int amd_iommu_xt_mode = IRQ_REMAP_X2APIC_MODE;
+static int amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
 
 static bool amd_iommu_detected;
 static bool __initdata amd_iommu_disabled;
@@ -1531,8 +1531,15 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 			iommu->mmio_phys_end = MMIO_CNTR_CONF_OFFSET;
 		if (((h->efr_reg & (0x1 << IOMMU_EFR_GASUP_SHIFT)) == 0))
 			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
-		if (((h->efr_reg & (0x1 << IOMMU_EFR_XTSUP_SHIFT)) == 0))
-			amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
+		/*
+		 * Note: Since iommu_update_intcapxt() leverages
+		 * the IOMMU MMIO access to MSI capability block registers
+		 * for MSI address lo/hi/data, we need to check both
+		 * EFR[XtSup] and EFR[MsiCapMmioSup] for x2APIC support.
+		 */
+		if ((h->efr_reg & BIT(IOMMU_EFR_XTSUP_SHIFT)) &&
+		    (h->efr_reg & BIT(IOMMU_EFR_MSICAPMMIOSUP_SHIFT)))
+			amd_iommu_xt_mode = IRQ_REMAP_X2APIC_MODE;
 		break;
 	default:
 		return -EINVAL;
@@ -1981,8 +1988,8 @@ static int iommu_init_intcapxt(struct amd_iommu *iommu)
 	struct irq_affinity_notify *notify = &iommu->intcapxt_notify;
 
 	/**
-	 * IntCapXT requires XTSup=1, which can be inferred
-	 * amd_iommu_xt_mode.
+	 * IntCapXT requires XTSup=1 and MsiCapMmioSup=1,
+	 * which can be inferred from amd_iommu_xt_mode.
 	 */
 	if (amd_iommu_xt_mode != IRQ_REMAP_X2APIC_MODE)
 		return 0;
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 34d63af..89b0c6e 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -383,6 +383,7 @@
 /* IOMMU Extended Feature Register (EFR) */
 #define IOMMU_EFR_XTSUP_SHIFT	2
 #define IOMMU_EFR_GASUP_SHIFT	7
+#define IOMMU_EFR_MSICAPMMIOSUP_SHIFT	46
 
 #define MAX_DOMAIN_ID 65536
 
-- 
1.8.3.1

[PATCH 2/2] iommu/amd: Only support x2APIC with IVHD type 11h/40h

[Suravee Suthikulpanit]

Current implementation for IOMMU x2APIC support makes use of
the MMIO access to MSI capability block registers, which requires
checking EFR[MsiCapMmioSup]. However, only IVHD type 11h/40h contain
the information, and not in the IVHD type 10h IOMMU feature reporting
field. Since the BIOS in newer systems, which supports x2APIC, would
normally contain IVHD type 11h/40h, remove the IOMMU_FEAT_XTSUP_SHIFT
check for IVHD type 10h, and only support x2APIC with IVHD type 11h/40h.

Fixes: 66929812955b ('iommu/amd: Add support for X2APIC IOMMU interrupts')
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd_iommu_init.c  | 2 --
 drivers/iommu/amd_iommu_types.h | 1 -
 2 files changed, 3 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 1dcc0b3..2be4020 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1520,8 +1520,6 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 			iommu->mmio_phys_end = MMIO_CNTR_CONF_OFFSET;
 		if (((h->efr_attr & (0x1 << IOMMU_FEAT_GASUP_SHIFT)) == 0))
 			amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
-		if (((h->efr_attr & (0x1 << IOMMU_FEAT_XTSUP_SHIFT)) == 0))
-			amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
 		break;
 	case 0x11:
 	case 0x40:
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 89b0c6e..3a94169 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -377,7 +377,6 @@
 #define IOMMU_CAP_EFR     27
 
 /* IOMMU Feature Reporting Field (for IVHD type 10h */
-#define IOMMU_FEAT_XTSUP_SHIFT	0
 #define IOMMU_FEAT_GASUP_SHIFT	6
 
 /* IOMMU Extended Feature Register (EFR) */
-- 
1.8.3.1

Re: [PATCH 0/2] iommu/amd: Fixes for x2APIC support

[Joerg Roedel]

On Wed, Nov 20, 2019 at 07:55:47AM -0600, Suravee Suthikulpanit wrote:
> Adding feature support check for MMIO access to MSI capability
> block registers when enabling x2APIC (XT) mode. Also fix up logic
> for checking XT feature support for IVHD type 10h.
> 
> Suravee Suthikulpanit (2):
>   iommu/amd: Check feature support bit before accessing MSI capability
>     registers
>   iommu/amd: Only support x2APIC with IVHD type 11h/40h

Applied both, thanks Suravee.