KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/arch/mips/rb532/setup.c b/arch/mips/rb532/setup.c
new file mode 100644
index 000000000..51af9d374
--- /dev/null
+++ b/arch/mips/rb532/setup.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * setup.c - boot time setup code
+ */
+
+#include <linux/init.h>
+#include <linux/export.h>
+
+#include <asm/bootinfo.h>
+#include <asm/reboot.h>
+#include <asm/time.h>
+#include <linux/ioport.h>
+
+#include <asm/mach-rc32434/rb.h>
+#include <asm/mach-rc32434/pci.h>
+
+struct pci_reg __iomem *pci_reg;
+EXPORT_SYMBOL(pci_reg);
+
+static struct resource pci0_res[] = {
+	{
+		.name = "pci_reg0",
+		.start = PCI0_BASE_ADDR,
+		.end = PCI0_BASE_ADDR + sizeof(struct pci_reg),
+		.flags = IORESOURCE_MEM,
+	}
+};
+
+static void rb_machine_restart(char *command)
+{
+	/* just jump to the reset vector */
+	writel(0x80000001, IDT434_REG_BASE + RST);
+	((void (*)(void)) KSEG1ADDR(0x1FC00000u))();
+}
+
+static void rb_machine_halt(void)
+{
+	for (;;)
+		continue;
+}
+
+void __init plat_mem_setup(void)
+{
+	u32 val;
+
+	_machine_restart = rb_machine_restart;
+	_machine_halt = rb_machine_halt;
+	pm_power_off = rb_machine_halt;
+
+	set_io_port_base(KSEG1);
+
+	pci_reg = ioremap(pci0_res[0].start,
+				pci0_res[0].end - pci0_res[0].start);
+	if (!pci_reg) {
+		printk(KERN_ERR "Could not remap PCI registers\n");
+		return;
+	}
+
+	val = __raw_readl(&pci_reg->pcic);
+	val &= 0xFFFFFF7;
+	__raw_writel(val, (void *)&pci_reg->pcic);
+
+#ifdef CONFIG_PCI
+	/* Enable PCI interrupts in EPLD Mask register */
+	*epld_mask = 0x0;
+	*(epld_mask + 1) = 0x0;
+#endif
+	write_c0_wired(0);
+}
+
+const char *get_system_type(void)
+{
+	switch (mips_machtype) {
+	case MACH_MIKROTIK_RB532A:
+		return "Mikrotik RB532A";
+		break;
+	default:
+		return "Mikrotik RB532";
+		break;
+	}
+}