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, 235 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
new file mode 100644
index 000000000..c5674161b
--- /dev/null
+++ b/drivers/usb/dwc3/host.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * host.c - DesignWare USB3 DRD Controller Host Glue
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com
+ *
+ * Authors: Felipe Balbi <balbi@ti.com>,
+ */
+
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/bitfield.h>
+
+#include "../host/xhci-port.h"
+#include "../host/xhci-ext-caps.h"
+#include "../host/xhci-caps.h"
+#include "../host/xhci-plat.h"
+#include "core.h"
+
+#define XHCI_HCSPARAMS1		0x4
+#define XHCI_PORTSC_BASE	0x400
+
+/**
+ * dwc3_power_off_all_roothub_ports - Power off all Root hub ports
+ * @dwc: Pointer to our controller context structure
+ */
+static void dwc3_power_off_all_roothub_ports(struct dwc3 *dwc)
+{
+	void __iomem *xhci_regs;
+	u32 op_regs_base;
+	int port_num;
+	u32 offset;
+	u32 reg;
+	int i;
+
+	/* xhci regs are not mapped yet, do it temporarily here */
+	if (dwc->xhci_resources[0].start) {
+		if (dwc->xhci_resources[0].flags & IORESOURCE_MEM_NONPOSTED)
+			xhci_regs = ioremap_np(dwc->xhci_resources[0].start, DWC3_XHCI_REGS_END);
+		else
+			xhci_regs = ioremap(dwc->xhci_resources[0].start, DWC3_XHCI_REGS_END);
+		if (!xhci_regs) {
+			dev_err(dwc->dev, "Failed to ioremap xhci_regs\n");
+			return;
+		}
+
+		op_regs_base = FIELD_GET(HC_LENGTH, readl(xhci_regs));
+		reg = readl(xhci_regs + XHCI_HCSPARAMS1);
+		port_num = FIELD_GET(HCS_MAX_PORTS, reg);
+
+		for (i = 1; i <= port_num; i++) {
+			offset = op_regs_base + XHCI_PORTSC_BASE + 0x10 * (i - 1);
+			reg = readl(xhci_regs + offset);
+			reg &= ~PORT_POWER;
+			writel(reg, xhci_regs + offset);
+		}
+
+		iounmap(xhci_regs);
+	} else {
+		dev_err(dwc->dev, "xhci base reg invalid\n");
+	}
+}
+
+static void dwc3_xhci_plat_start(struct usb_hcd *hcd)
+{
+	struct platform_device *pdev;
+	struct dwc3 *dwc;
+
+	if (!usb_hcd_is_primary_hcd(hcd))
+		return;
+
+	pdev = to_platform_device(hcd->self.controller);
+	dwc = dev_get_drvdata(pdev->dev.parent);
+
+	dwc3_enable_susphy(dwc, true);
+}
+
+static const struct xhci_plat_priv dwc3_xhci_plat_quirk = {
+	.plat_start = dwc3_xhci_plat_start,
+};
+
+static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
+					int irq, char *name)
+{
+	struct platform_device *pdev = to_platform_device(dwc->dev);
+	struct device_node *np = dev_of_node(&pdev->dev);
+
+	dwc->xhci_resources[1].start = irq;
+	dwc->xhci_resources[1].end = irq;
+	dwc->xhci_resources[1].flags = IORESOURCE_IRQ | irq_get_trigger_type(irq);
+	if (!name && np)
+		dwc->xhci_resources[1].name = of_node_full_name(pdev->dev.of_node);
+	else
+		dwc->xhci_resources[1].name = name;
+}
+
+static int dwc3_host_get_irq(struct dwc3 *dwc)
+{
+	struct platform_device	*dwc3_pdev = to_platform_device(dwc->dev);
+	int irq;
+
+	irq = platform_get_irq_byname_optional(dwc3_pdev, "host");
+	if (irq > 0) {
+		dwc3_host_fill_xhci_irq_res(dwc, irq, "host");
+		goto out;
+	}
+
+	if (irq == -EPROBE_DEFER)
+		goto out;
+
+	irq = platform_get_irq_byname_optional(dwc3_pdev, "dwc_usb3");
+	if (irq > 0) {
+		dwc3_host_fill_xhci_irq_res(dwc, irq, "dwc_usb3");
+		goto out;
+	}
+
+	if (irq == -EPROBE_DEFER)
+		goto out;
+
+	irq = platform_get_irq(dwc3_pdev, 0);
+	if (irq > 0)
+		dwc3_host_fill_xhci_irq_res(dwc, irq, NULL);
+
+out:
+	return irq;
+}
+
+int dwc3_host_init(struct dwc3 *dwc)
+{
+	struct property_entry	props[6];
+	struct platform_device	*xhci;
+	int			ret, irq;
+	int			prop_idx = 0;
+
+	/*
+	 * Some platforms need to power off all Root hub ports immediately after DWC3 set to host
+	 * mode to avoid VBUS glitch happen when xhci get reset later.
+	 */
+	dwc3_power_off_all_roothub_ports(dwc);
+
+	irq = dwc3_host_get_irq(dwc);
+	if (irq < 0)
+		return irq;
+
+	xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
+	if (!xhci) {
+		dev_err(dwc->dev, "couldn't allocate xHCI device\n");
+		return -ENOMEM;
+	}
+
+	xhci->dev.parent	= dwc->dev;
+
+	dwc->xhci = xhci;
+
+	ret = platform_device_add_resources(xhci, dwc->xhci_resources,
+						DWC3_XHCI_RESOURCES_NUM);
+	if (ret) {
+		dev_err(dwc->dev, "couldn't add resources to xHCI device\n");
+		goto err;
+	}
+
+	memset(props, 0, sizeof(struct property_entry) * ARRAY_SIZE(props));
+
+	props[prop_idx++] = PROPERTY_ENTRY_BOOL("xhci-sg-trb-cache-size-quirk");
+
+	props[prop_idx++] = PROPERTY_ENTRY_BOOL("write-64-hi-lo-quirk");
+
+	if (dwc->usb3_lpm_capable)
+		props[prop_idx++] = PROPERTY_ENTRY_BOOL("usb3-lpm-capable");
+
+	if (dwc->usb2_lpm_disable)
+		props[prop_idx++] = PROPERTY_ENTRY_BOOL("usb2-lpm-disable");
+
+	/**
+	 * WORKAROUND: dwc3 revisions <=3.00a have a limitation
+	 * where Port Disable command doesn't work.
+	 *
+	 * The suggested workaround is that we avoid Port Disable
+	 * completely.
+	 *
+	 * This following flag tells XHCI to do just that.
+	 */
+	if (DWC3_VER_IS_WITHIN(DWC3, ANY, 300A))
+		props[prop_idx++] = PROPERTY_ENTRY_BOOL("quirk-broken-port-ped");
+
+	props[prop_idx++] = PROPERTY_ENTRY_U16("num-hc-interrupters",
+					       dwc->num_hc_interrupters);
+
+	if (prop_idx) {
+		ret = device_create_managed_software_node(&xhci->dev, props, NULL);
+		if (ret) {
+			dev_err(dwc->dev, "failed to add properties to xHCI\n");
+			goto err;
+		}
+	}
+
+	ret = platform_device_add_data(xhci, &dwc3_xhci_plat_quirk,
+				       sizeof(struct xhci_plat_priv));
+	if (ret)
+		goto err;
+
+	ret = platform_device_add(xhci);
+	if (ret) {
+		dev_err(dwc->dev, "failed to register xHCI device\n");
+		goto err;
+	}
+
+	if (dwc->sys_wakeup) {
+		/* Restore wakeup setting if switched from device */
+		device_wakeup_enable(dwc->sysdev);
+
+		/* Pass on wakeup setting to the new xhci platform device */
+		device_init_wakeup(&xhci->dev, true);
+	}
+
+	return 0;
+err:
+	platform_device_put(xhci);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dwc3_host_init);
+
+void dwc3_host_exit(struct dwc3 *dwc)
+{
+	if (dwc->sys_wakeup)
+		device_init_wakeup(&dwc->xhci->dev, false);
+
+	dwc3_enable_susphy(dwc, true);
+	platform_device_unregister(dwc->xhci);
+	dwc->xhci = NULL;
+}
+EXPORT_SYMBOL_GPL(dwc3_host_exit);