[PATCH v7 1/6] x86/msi: Extend per-domain/device warning mechanism

[Marek Marczykowski-Górecki]

The arch_msix struct had a single "warned" field with a domid for which
warning was issued. Upcoming patch will need similar mechanism for few
more warnings, so change it to save a bit field of issued warnings.

Signed-off-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com>
---
Changes in v6:
- add MSIX_CHECK_WARN macro (Jan)
- drop struct name from warned_kind union (Jan)

New in v5
---
 xen/arch/x86/include/asm/msi.h | 17 ++++++++++++++++-
 xen/arch/x86/msi.c             |  5 +----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/include/asm/msi.h b/xen/arch/x86/include/asm/msi.h
index 997ccb87be0c..bcfdfd35345d 100644
--- a/xen/arch/x86/include/asm/msi.h
+++ b/xen/arch/x86/include/asm/msi.h
@@ -208,6 +208,15 @@ struct msg_address {
                                        PCI_MSIX_ENTRY_SIZE + \
                                        (~PCI_MSIX_BIRMASK & (PAGE_SIZE - 1)))
 
+#define MSIX_CHECK_WARN(msix, domid, which) ({ \
+    if ( (msix)->warned_domid != (domid) ) \
+    { \
+        (msix)->warned_domid = (domid); \
+        (msix)->warned_kind.all = 0; \
+    } \
+    (msix)->warned_kind.which ? false : ((msix)->warned_kind.which = true); \
+})
+
 struct arch_msix {
     unsigned int nr_entries, used_entries;
     struct {
@@ -217,7 +226,13 @@ struct arch_msix {
     int table_idx[MAX_MSIX_TABLE_PAGES];
     spinlock_t table_lock;
     bool host_maskall, guest_maskall;
-    domid_t warned;
+    domid_t warned_domid;
+    union {
+        uint8_t all;
+        struct {
+            bool maskall                   : 1;
+        };
+    } warned_kind;
 };
 
 void early_msi_init(void);
diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c
index e721aaf5c001..42c793426da3 100644
--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -364,13 +364,10 @@ static bool msi_set_mask_bit(struct irq_desc *desc, bool 
host, bool guest)
             domid_t domid = pdev->domain->domain_id;
 
             maskall = true;
-            if ( pdev->msix->warned != domid )
-            {
-                pdev->msix->warned = domid;
+            if ( MSIX_CHECK_WARN(pdev->msix, domid, maskall) )
                 printk(XENLOG_G_WARNING
                        "cannot mask IRQ %d: masking MSI-X on Dom%d's %pp\n",
                        desc->irq, domid, &pdev->sbdf);
-            }
         }
         pdev->msix->host_maskall = maskall;
         if ( maskall || pdev->msix->guest_maskall )
-- 
git-series 0.9.1