Re: [PATCH v6 2/7] x86/msi: Extend per-domain/device warning mechanism

[Jan Beulich]

On 26.04.2024 19:53, Marek Marczykowski-Górecki wrote:
> 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 

Reviewed-by: Jan Beulich 
(if that makes sense at all, considering that one fundamental part of it,
the macro, was suggested by me)

However, unlike at other times I'd like this to go in only together with
the following patch (or whatever other 2nd user of the new machinery).

Jan

[PATCH v6 2/7] 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 
---
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, >sbdf);
-}
 }
 pdev->msix->host_maskall = maskall;
 if ( maskall || pdev->msix->guest_maskall )
-- 
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