On certain systems configured with 4K PAGE_SIZE, utilizing page_pool
fragments for RX buffers results in a significant throughput regression.
Profiling reveals that this regression correlates with high overhead in the
fragment allocation and reference counting paths on these specific
platforms, rendering the multi-buffer-per-page strategy counterproductive.

To mitigate this, bypass the page_pool fragment path and force a single RX
packet per page allocation when all the following conditions are met:
  1. The system is configured with a 4K PAGE_SIZE.
  2. A processor-specific quirk is detected via SMBIOS Type 4 data.

This approach restores expected line-rate performance by ensuring
predictable RX refill behavior on affected hardware.

There is no behavioral change for systems using larger page sizes
(16K/64K), or platforms where this processor-specific quirk do not
apply.

Signed-off-by: Dipayaan Roy <redacted>
---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 120 ++++++++++++++++++
 drivers/net/ethernet/microsoft/mana/mana_en.c |  23 +++-
 include/net/mana/gdma.h                       |  10 ++
 3 files changed, 151 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 0055c231acf6..26bbe736a770 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c

@@ -9,6 +9,7 @@
 #include <linux/msi.h>
 #include <linux/irqdomain.h>
 #include <linux/export.h>
+#include <linux/dmi.h>
 
 #include <net/mana/mana.h>
 #include <net/mana/hw_channel.h>

@@ -1955,6 +1956,115 @@ static bool mana_is_pf(unsigned short dev_id)
 	return dev_id == MANA_PF_DEVICE_ID;
 }
 
+/*
+ * Table for Processor Version strings found from SMBIOS Type 4 information,
+ * for processors that needs to force single RX buffer per page quirk for
+ * meeting line rate performance with ARM64 + 4K pages.
+ * Note: These strings are exactly matched with version fetched from SMBIOS.
+ */
+static const char * const mana_single_rxbuf_per_page_quirk_tbl[] = {
+	"Cobalt 200",
+};
+
+static const char *smbios_get_string(const struct dmi_header *hdr, u8 idx)
+{
+	const u8 *start, *end;
+	u8 i;
+
+	/* Indexing starts from 1. */
+	if (!idx)
+		return NULL;
+
+	start   = (const u8 *)hdr + hdr->length;
+	end = start + SMBIOS_STR_AREA_MAX;
+
+	for (i = 1; i < idx; i++) {
+		while (start < end && *start)
+			start++;
+		if (start < end)
+			start++;
+		if (start + 1 < end && start[0] == 0 && start[1] == 0)
+			return NULL;
+	}
+
+	if (start >= end || *start == 0)
+		return NULL;
+
+	return (const char *)start;