[Xen-devel] [PATCH] xen/arm: Drop support of platform where GICH_LR_HW is not working correctly

[Julien Grall <julien.grall@xxxxxxxxxx>]

Until recently, a maintenance IRQ was requested for any IRQ injected to
the guest on x-gene platform.

The commit 50dcb3de603927db2fd87ba09e29c817415aaa44 "xen: arm: X-Gene Storm
check GIC DIST address for EOI quirk" disable the quirk for boards using
the new firmware.

It is known that the quirk is fragile and cause performance regression.
Given that firmware is available for people having the board, I think
we can request the user to upgrade to the latest version.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
Cc: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>

---

Ref: http://lists.xen.org/archives/html/xen-devel/2015-05/msg00801.html
---
 xen/arch/arm/gic-hip04.c             |  9 ++-------
 xen/arch/arm/gic-v2.c                |  9 ++-------
 xen/arch/arm/gic.c                   |  4 ----
 xen/arch/arm/platforms/xgene-storm.c | 15 ++++++---------
 xen/include/asm-arm/platform.h       |  5 -----
 5 files changed, 10 insertions(+), 32 deletions(-)

diff --git a/xen/arch/arm/gic-hip04.c b/xen/arch/arm/gic-hip04.c
index 5dcd894..ee693e7 100644
--- a/xen/arch/arm/gic-hip04.c
+++ b/xen/arch/arm/gic-hip04.c
@@ -423,13 +423,8 @@ static void hip04gic_update_lr(int lr, const struct 
pending_irq *p,
               ((p->irq & GICH_V2_LR_VIRTUAL_MASK) << 
GICH_V2_LR_VIRTUAL_SHIFT));
 
     if ( p->desc != NULL )
-    {
-        if ( platform_has_quirk(PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI) )
-            lr_reg |= GICH_V2_LR_MAINTENANCE_IRQ;
-        else
-            lr_reg |= GICH_V2_LR_HW | ((p->desc->irq & 
GICH_V2_LR_PHYSICAL_MASK )
-                            << GICH_V2_LR_PHYSICAL_SHIFT);
-    }
+        lr_reg |= GICH_V2_LR_HW | ((p->desc->irq & GICH_V2_LR_PHYSICAL_MASK )
+                                   << GICH_V2_LR_PHYSICAL_SHIFT);
 
     writel_gich(lr_reg, HIP04_GICH_LR + lr * 4);
 }
diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 80acc62..edf659b 100644
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -413,13 +413,8 @@ static void gicv2_update_lr(int lr, const struct 
pending_irq *p,
               ((p->irq & GICH_V2_LR_VIRTUAL_MASK) << 
GICH_V2_LR_VIRTUAL_SHIFT));
 
     if ( p->desc != NULL )
-    {
-        if ( platform_has_quirk(PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI) )
-            lr_reg |= GICH_V2_LR_MAINTENANCE_IRQ;
-        else
-            lr_reg |= GICH_V2_LR_HW | ((p->desc->irq & 
GICH_V2_LR_PHYSICAL_MASK )
-                            << GICH_V2_LR_PHYSICAL_SHIFT);
-    }
+        lr_reg |= GICH_V2_LR_HW | ((p->desc->irq & GICH_V2_LR_PHYSICAL_MASK )
+                                   << GICH_V2_LR_PHYSICAL_SHIFT);
 
     writel_gich(lr_reg, GICH_LR + lr * 4);
 }
diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index 125298c..c41e82e 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -445,11 +445,7 @@ static void gic_update_one_lr(struct vcpu *v, int i)
         clear_bit(i, &this_cpu(lr_mask));
 
         if ( p->desc != NULL )
-        {
             clear_bit(_IRQ_INPROGRESS, &p->desc->status);
-            if ( platform_has_quirk(PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI) )
-                gic_hw_ops->deactivate_irq(p->desc);
-        }
         clear_bit(GIC_IRQ_GUEST_VISIBLE, &p->status);
         clear_bit(GIC_IRQ_GUEST_ACTIVE, &p->status);
         p->lr = GIC_INVALID_LR;
diff --git a/xen/arch/arm/platforms/xgene-storm.c 
b/xen/arch/arm/platforms/xgene-storm.c
index c717360..1362bea 100644
--- a/xen/arch/arm/platforms/xgene-storm.c
+++ b/xen/arch/arm/platforms/xgene-storm.c
@@ -37,7 +37,6 @@ static u32 reset_mask;
 static bool reset_vals_valid = false;
 
 #define XGENE_SEC_GICV2_DIST_ADDR    0x78010000
-static u32 __read_mostly xgene_quirks = PLATFORM_QUIRK_GIC_64K_STRIDE;
 
 static void __init xgene_check_pirq_eoi(void)
 {
@@ -60,20 +59,18 @@ static void __init xgene_check_pirq_eoi(void)
 
     /*
      * In old X-Gene Storm firmware and DT, secure mode addresses have
-     * been mentioned in GICv2 node. We have to use maintenance interrupt
-     * instead of EOI HW in this case. We check the GIC Distributor Base
-     * Address to maintain compatibility with older firmware.
+     * been mentioned in GICv2 node. EOI HW won't work in this case.
+     * We check the GIC Distributor Base Address to deny Xen booting
+     * with older firmware.
      */
     if ( dbase == XGENE_SEC_GICV2_DIST_ADDR )
-    {
-        xgene_quirks |= PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI;
-        printk("Xen: WARNING: OLD X-Gene Firmware, disabling PIRQ EOI mode\n");
-    }
+        panic("OLD X-Gene Firmware is not supported by Xen.\n"
+              "Please upgrade your firmware to the latest version");
 }
 
 static uint32_t xgene_storm_quirks(void)
 {
-    return xgene_quirks;
+    return PLATFORM_QUIRK_GIC_64K_STRIDE;
 }
 
 static int map_one_mmio(struct domain *d, const char *what,
diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
index 4eba37b..746e126 100644
--- a/xen/include/asm-arm/platform.h
+++ b/xen/include/asm-arm/platform.h
@@ -51,11 +51,6 @@ struct platform_desc {
  */
 #define PLATFORM_QUIRK_GIC_64K_STRIDE (1 << 0)
 
-/*
- * Quirk for platforms where GICH_LR_HW does not work as expected.
- */
-#define PLATFORM_QUIRK_GUEST_PIRQ_NEED_EOI       (1 << 1)
-
 void __init platform_init(void);
 int __init platform_init_time(void);
 int __init platform_specific_mapping(struct domain *d);
-- 
2.1.4


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