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, 254 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-ps3.c b/drivers/usb/host/ehci-ps3.c
new file mode 100644
index 000000000..98568b046
--- /dev/null
+++ b/drivers/usb/host/ehci-ps3.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  PS3 EHCI Host Controller driver
+ *
+ *  Copyright (C) 2006 Sony Computer Entertainment Inc.
+ *  Copyright 2006 Sony Corp.
+ */
+
+#include <asm/firmware.h>
+#include <asm/ps3.h>
+
+static void ps3_ehci_setup_insnreg(struct ehci_hcd *ehci)
+{
+	/* PS3 HC internal setup register offsets. */
+
+	enum ps3_ehci_hc_insnreg {
+		ps3_ehci_hc_insnreg01 = 0x084,
+		ps3_ehci_hc_insnreg02 = 0x088,
+		ps3_ehci_hc_insnreg03 = 0x08c,
+	};
+
+	/* PS3 EHCI HC errata fix 316 - The PS3 EHCI HC will reset its
+	 * internal INSNREGXX setup regs back to the chip default values
+	 * on Host Controller Reset (CMD_RESET) or Light Host Controller
+	 * Reset (CMD_LRESET).  The work-around for this is for the HC
+	 * driver to re-initialise these regs when ever the HC is reset.
+	 */
+
+	/* Set burst transfer counts to 256 out, 32 in. */
+
+	writel_be(0x01000020, (void __iomem *)ehci->regs +
+		ps3_ehci_hc_insnreg01);
+
+	/* Enable burst transfer counts. */
+
+	writel_be(0x00000001, (void __iomem *)ehci->regs +
+		ps3_ehci_hc_insnreg03);
+}
+
+static int ps3_ehci_hc_reset(struct usb_hcd *hcd)
+{
+	int result;
+	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+
+	ehci->big_endian_mmio = 1;
+	ehci->caps = hcd->regs;
+
+	result = ehci_setup(hcd);
+	if (result)
+		return result;
+
+	ps3_ehci_setup_insnreg(ehci);
+
+	return result;
+}
+
+static const struct hc_driver ps3_ehci_hc_driver = {
+	.description		= hcd_name,
+	.product_desc		= "PS3 EHCI Host Controller",
+	.hcd_priv_size		= sizeof(struct ehci_hcd),
+	.irq			= ehci_irq,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,
+	.reset			= ps3_ehci_hc_reset,
+	.start			= ehci_run,
+	.stop			= ehci_stop,
+	.shutdown		= ehci_shutdown,
+	.urb_enqueue		= ehci_urb_enqueue,
+	.urb_dequeue		= ehci_urb_dequeue,
+	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
+	.get_frame_number	= ehci_get_frame,
+	.hub_status_data	= ehci_hub_status_data,
+	.hub_control		= ehci_hub_control,
+#if defined(CONFIG_PM)
+	.bus_suspend		= ehci_bus_suspend,
+	.bus_resume		= ehci_bus_resume,
+#endif
+	.relinquish_port	= ehci_relinquish_port,
+	.port_handed_over	= ehci_port_handed_over,
+
+	.clear_tt_buffer_complete	= ehci_clear_tt_buffer_complete,
+};
+
+static int ps3_ehci_probe(struct ps3_system_bus_device *dev)
+{
+	int result;
+	struct usb_hcd *hcd;
+	unsigned int virq;
+	static u64 dummy_mask;
+
+	if (usb_disabled()) {
+		result = -ENODEV;
+		goto fail_start;
+	}
+
+	result = ps3_open_hv_device(dev);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_open_hv_device failed\n",
+			__func__, __LINE__);
+		goto fail_open;
+	}
+
+	result = ps3_dma_region_create(dev->d_region);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_dma_region_create failed: "
+			"(%d)\n", __func__, __LINE__, result);
+		BUG_ON("check region type");
+		goto fail_dma_region;
+	}
+
+	result = ps3_mmio_region_create(dev->m_region);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_map_mmio_region failed\n",
+			__func__, __LINE__);
+		result = -EPERM;
+		goto fail_mmio_region;
+	}
+
+	dev_dbg(&dev->core, "%s:%d: mmio mapped_addr %lxh\n", __func__,
+		__LINE__, dev->m_region->lpar_addr);
+
+	result = ps3_io_irq_setup(PS3_BINDING_CPU_ANY, dev->interrupt_id, &virq);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_construct_io_irq(%d) failed.\n",
+			__func__, __LINE__, virq);
+		result = -EPERM;
+		goto fail_irq;
+	}
+
+	dummy_mask = DMA_BIT_MASK(32);
+	dev->core.dma_mask = &dummy_mask;
+	dma_set_coherent_mask(&dev->core, dummy_mask);
+
+	hcd = usb_create_hcd(&ps3_ehci_hc_driver, &dev->core, dev_name(&dev->core));
+
+	if (!hcd) {
+		dev_dbg(&dev->core, "%s:%d: usb_create_hcd failed\n", __func__,
+			__LINE__);
+		result = -ENOMEM;
+		goto fail_create_hcd;
+	}
+
+	hcd->rsrc_start = dev->m_region->lpar_addr;
+	hcd->rsrc_len = dev->m_region->len;
+
+	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name))
+		dev_dbg(&dev->core, "%s:%d: request_mem_region failed\n",
+			__func__, __LINE__);
+
+	hcd->regs = ioremap(dev->m_region->lpar_addr, dev->m_region->len);
+
+	if (!hcd->regs) {
+		dev_dbg(&dev->core, "%s:%d: ioremap failed\n", __func__,
+			__LINE__);
+		result = -EPERM;
+		goto fail_ioremap;
+	}
+
+	dev_dbg(&dev->core, "%s:%d: hcd->rsrc_start %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->rsrc_start);
+	dev_dbg(&dev->core, "%s:%d: hcd->rsrc_len   %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->rsrc_len);
+	dev_dbg(&dev->core, "%s:%d: hcd->regs       %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->regs);
+	dev_dbg(&dev->core, "%s:%d: virq            %lu\n", __func__, __LINE__,
+		(unsigned long)virq);
+
+	ps3_system_bus_set_drvdata(dev, hcd);
+
+	result = usb_add_hcd(hcd, virq, 0);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: usb_add_hcd failed (%d)\n",
+			__func__, __LINE__, result);
+		goto fail_add_hcd;
+	}
+
+	device_wakeup_enable(hcd->self.controller);
+	return result;
+
+fail_add_hcd:
+	iounmap(hcd->regs);
+fail_ioremap:
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+	usb_put_hcd(hcd);
+fail_create_hcd:
+	ps3_io_irq_destroy(virq);
+fail_irq:
+	ps3_free_mmio_region(dev->m_region);
+fail_mmio_region:
+	ps3_dma_region_free(dev->d_region);
+fail_dma_region:
+	ps3_close_hv_device(dev);
+fail_open:
+fail_start:
+	return result;
+}
+
+static void ps3_ehci_remove(struct ps3_system_bus_device *dev)
+{
+	unsigned int tmp;
+	struct usb_hcd *hcd = ps3_system_bus_get_drvdata(dev);
+
+	BUG_ON(!hcd);
+
+	dev_dbg(&dev->core, "%s:%d: regs %p\n", __func__, __LINE__, hcd->regs);
+	dev_dbg(&dev->core, "%s:%d: irq %u\n", __func__, __LINE__, hcd->irq);
+
+	tmp = hcd->irq;
+
+	usb_remove_hcd(hcd);
+
+	ps3_system_bus_set_drvdata(dev, NULL);
+
+	BUG_ON(!hcd->regs);
+	iounmap(hcd->regs);
+
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+	usb_put_hcd(hcd);
+
+	ps3_io_irq_destroy(tmp);
+	ps3_free_mmio_region(dev->m_region);
+
+	ps3_dma_region_free(dev->d_region);
+	ps3_close_hv_device(dev);
+}
+
+static int __init ps3_ehci_driver_register(struct ps3_system_bus_driver *drv)
+{
+	return firmware_has_feature(FW_FEATURE_PS3_LV1)
+		? ps3_system_bus_driver_register(drv)
+		: 0;
+}
+
+static void ps3_ehci_driver_unregister(struct ps3_system_bus_driver *drv)
+{
+	if (firmware_has_feature(FW_FEATURE_PS3_LV1))
+		ps3_system_bus_driver_unregister(drv);
+}
+
+MODULE_ALIAS(PS3_MODULE_ALIAS_EHCI);
+
+static struct ps3_system_bus_driver ps3_ehci_driver = {
+	.core.name = "ps3-ehci-driver",
+	.core.owner = THIS_MODULE,
+	.match_id = PS3_MATCH_ID_EHCI,
+	.probe = ps3_ehci_probe,
+	.remove = ps3_ehci_remove,
+	.shutdown = ps3_ehci_remove,
+};