KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 271 insertions, 0 deletions

diff --git a/arch/mips/ath79/setup.c b/arch/mips/ath79/setup.c
new file mode 100644
index 000000000..4e18cdcf6
--- /dev/null
+++ b/arch/mips/ath79/setup.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Atheros AR71XX/AR724X/AR913X specific setup
+ *
+ *  Copyright (C) 2010-2011 Jaiganesh Narayanan <jnarayanan@atheros.com>
+ *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  Parts of this file are based on Atheros' 2.6.15/2.6.31 BSP
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/of_clk.h>
+#include <linux/of_fdt.h>
+#include <linux/irqchip.h>
+
+#include <asm/bootinfo.h>
+#include <asm/idle.h>
+#include <asm/time.h>		/* for mips_hpt_frequency */
+#include <asm/reboot.h>		/* for _machine_{restart,halt} */
+#include <asm/prom.h>
+#include <asm/fw/fw.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+
+#define ATH79_SYS_TYPE_LEN	64
+
+static char ath79_sys_type[ATH79_SYS_TYPE_LEN];
+
+static void ath79_halt(void)
+{
+	while (1)
+		cpu_wait();
+}
+
+static void __init ath79_detect_sys_type(void)
+{
+	char *chip = "????";
+	u32 id;
+	u32 major;
+	u32 minor;
+	u32 rev = 0;
+	u32 ver = 1;
+
+	id = ath79_reset_rr(AR71XX_RESET_REG_REV_ID);
+	major = id & REV_ID_MAJOR_MASK;
+
+	switch (major) {
+	case REV_ID_MAJOR_AR71XX:
+		minor = id & AR71XX_REV_ID_MINOR_MASK;
+		rev = id >> AR71XX_REV_ID_REVISION_SHIFT;
+		rev &= AR71XX_REV_ID_REVISION_MASK;
+		switch (minor) {
+		case AR71XX_REV_ID_MINOR_AR7130:
+			ath79_soc = ATH79_SOC_AR7130;
+			chip = "7130";
+			break;
+
+		case AR71XX_REV_ID_MINOR_AR7141:
+			ath79_soc = ATH79_SOC_AR7141;
+			chip = "7141";
+			break;
+
+		case AR71XX_REV_ID_MINOR_AR7161:
+			ath79_soc = ATH79_SOC_AR7161;
+			chip = "7161";
+			break;
+		}
+		break;
+
+	case REV_ID_MAJOR_AR7240:
+		ath79_soc = ATH79_SOC_AR7240;
+		chip = "7240";
+		rev = id & AR724X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR7241:
+		ath79_soc = ATH79_SOC_AR7241;
+		chip = "7241";
+		rev = id & AR724X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR7242:
+		ath79_soc = ATH79_SOC_AR7242;
+		chip = "7242";
+		rev = id & AR724X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR913X:
+		minor = id & AR913X_REV_ID_MINOR_MASK;
+		rev = id >> AR913X_REV_ID_REVISION_SHIFT;
+		rev &= AR913X_REV_ID_REVISION_MASK;
+		switch (minor) {
+		case AR913X_REV_ID_MINOR_AR9130:
+			ath79_soc = ATH79_SOC_AR9130;
+			chip = "9130";
+			break;
+
+		case AR913X_REV_ID_MINOR_AR9132:
+			ath79_soc = ATH79_SOC_AR9132;
+			chip = "9132";
+			break;
+		}
+		break;
+
+	case REV_ID_MAJOR_AR9330:
+		ath79_soc = ATH79_SOC_AR9330;
+		chip = "9330";
+		rev = id & AR933X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR9331:
+		ath79_soc = ATH79_SOC_AR9331;
+		chip = "9331";
+		rev = id & AR933X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR9341:
+		ath79_soc = ATH79_SOC_AR9341;
+		chip = "9341";
+		rev = id & AR934X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR9342:
+		ath79_soc = ATH79_SOC_AR9342;
+		chip = "9342";
+		rev = id & AR934X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_AR9344:
+		ath79_soc = ATH79_SOC_AR9344;
+		chip = "9344";
+		rev = id & AR934X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_QCA9533_V2:
+		ver = 2;
+		ath79_soc_rev = 2;
+		fallthrough;
+	case REV_ID_MAJOR_QCA9533:
+		ath79_soc = ATH79_SOC_QCA9533;
+		chip = "9533";
+		rev = id & QCA953X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_QCA9556:
+		ath79_soc = ATH79_SOC_QCA9556;
+		chip = "9556";
+		rev = id & QCA955X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_QCA9558:
+		ath79_soc = ATH79_SOC_QCA9558;
+		chip = "9558";
+		rev = id & QCA955X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_QCA956X:
+		ath79_soc = ATH79_SOC_QCA956X;
+		chip = "956X";
+		rev = id & QCA956X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_QCN550X:
+		ath79_soc = ATH79_SOC_QCA956X;
+		chip = "550X";
+		rev = id & QCA956X_REV_ID_REVISION_MASK;
+		break;
+
+	case REV_ID_MAJOR_TP9343:
+		ath79_soc = ATH79_SOC_TP9343;
+		chip = "9343";
+		rev = id & QCA956X_REV_ID_REVISION_MASK;
+		break;
+
+	default:
+		panic("ath79: unknown SoC, id:0x%08x", id);
+	}
+
+	if (ver == 1)
+		ath79_soc_rev = rev;
+
+	if (soc_is_qca953x() || soc_is_qca955x() || soc_is_qca956x())
+		sprintf(ath79_sys_type, "Qualcomm Atheros QCA%s ver %u rev %u",
+			chip, ver, rev);
+	else if (soc_is_tp9343())
+		sprintf(ath79_sys_type, "Qualcomm Atheros TP%s rev %u",
+			chip, rev);
+	else
+		sprintf(ath79_sys_type, "Atheros AR%s rev %u", chip, rev);
+	pr_info("SoC: %s\n", ath79_sys_type);
+}
+
+const char *get_system_type(void)
+{
+	return ath79_sys_type;
+}
+
+unsigned int get_c0_compare_int(void)
+{
+	return CP0_LEGACY_COMPARE_IRQ;
+}
+
+void __init plat_mem_setup(void)
+{
+	void *dtb;
+
+	set_io_port_base(KSEG1);
+
+	/* Get the position of the FDT passed by the bootloader */
+	dtb = (void *)fw_getenvl("fdt_start");
+	if (dtb == NULL)
+		dtb = get_fdt();
+
+	if (dtb)
+		__dt_setup_arch((void *)KSEG0ADDR(dtb));
+
+	ath79_reset_base = ioremap(AR71XX_RESET_BASE,
+					   AR71XX_RESET_SIZE);
+	ath79_pll_base = ioremap(AR71XX_PLL_BASE,
+					 AR71XX_PLL_SIZE);
+	ath79_detect_sys_type();
+	ath79_ddr_ctrl_init();
+
+	detect_memory_region(0, ATH79_MEM_SIZE_MIN, ATH79_MEM_SIZE_MAX);
+
+	_machine_halt = ath79_halt;
+	pm_power_off = ath79_halt;
+}
+
+void __init plat_time_init(void)
+{
+	struct device_node *np;
+	struct clk *clk;
+	unsigned long cpu_clk_rate;
+
+	of_clk_init(NULL);
+
+	np = of_get_cpu_node(0, NULL);
+	if (!np) {
+		pr_err("Failed to get CPU node\n");
+		return;
+	}
+
+	clk = of_clk_get(np, 0);
+	if (IS_ERR(clk)) {
+		pr_err("Failed to get CPU clock: %ld\n", PTR_ERR(clk));
+		return;
+	}
+
+	cpu_clk_rate = clk_get_rate(clk);
+
+	pr_info("CPU clock: %lu.%03lu MHz\n",
+		cpu_clk_rate / 1000000, (cpu_clk_rate / 1000) % 1000);
+
+	mips_hpt_frequency = cpu_clk_rate / 2;
+
+	clk_put(clk);
+}
+
+void __init arch_init_irq(void)
+{
+	irqchip_init();
+}