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, 190 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
new file mode 100644
index 000000000..a83751cfd
--- /dev/null
+++ b/drivers/crypto/ccp/sp-dev.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * AMD Secure Processor driver
+ *
+ * Copyright (C) 2017-2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ * Author: Gary R Hook <gary.hook@amd.com>
+ * Author: Brijesh Singh <brijesh.singh@amd.com>
+ */
+
+#ifndef __SP_DEV_H__
+#define __SP_DEV_H__
+
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/dmapool.h>
+#include <linux/hw_random.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+
+#define SP_MAX_NAME_LEN		32
+
+#define CACHE_NONE			0x00
+#define CACHE_WB_NO_ALLOC		0xb7
+
+#define PLATFORM_FEATURE_DBC		0x1
+#define PLATFORM_FEATURE_HSTI		0x2
+
+#define PSP_FEATURE(psp, feat)	(psp->vdata && psp->vdata->platform_features & PLATFORM_FEATURE_##feat)
+
+/* Structure to hold CCP device data */
+struct ccp_device;
+struct ccp_vdata {
+	const unsigned int version;
+	const unsigned int dma_chan_attr;
+	void (*setup)(struct ccp_device *);
+	const struct ccp_actions *perform;
+	const unsigned int offset;
+	const unsigned int rsamax;
+};
+
+struct sev_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+};
+
+struct tee_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int ring_wptr_reg;
+	const unsigned int ring_rptr_reg;
+	const unsigned int info_reg;
+};
+
+struct platform_access_vdata {
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int doorbell_button_reg;
+	const unsigned int doorbell_cmd_reg;
+
+};
+
+struct psp_vdata {
+	const struct sev_vdata *sev;
+	const struct tee_vdata *tee;
+	const struct platform_access_vdata *platform_access;
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
+	const unsigned int feature_reg;
+	const unsigned int inten_reg;
+	const unsigned int intsts_reg;
+	const unsigned int bootloader_info_reg;
+	const unsigned int platform_features;
+};
+
+/* Structure to hold SP device data */
+struct sp_dev_vdata {
+	const unsigned int bar;
+
+	const struct ccp_vdata *ccp_vdata;
+	const struct psp_vdata *psp_vdata;
+};
+
+struct sp_device {
+	struct list_head entry;
+
+	struct device *dev;
+
+	const struct sp_dev_vdata *dev_vdata;
+	unsigned int ord;
+	char name[SP_MAX_NAME_LEN];
+
+	/* Bus specific device information */
+	void *dev_specific;
+
+	/* I/O area used for device communication. */
+	void __iomem *io_map;
+
+	/* DMA caching attribute support */
+	unsigned int axcache;
+
+	/* get and set master device */
+	struct sp_device*(*get_psp_master_device)(void);
+	void (*set_psp_master_device)(struct sp_device *);
+	void (*clear_psp_master_device)(struct sp_device *);
+
+	bool irq_registered;
+	bool use_tasklet;
+
+	unsigned int ccp_irq;
+	irq_handler_t ccp_irq_handler;
+	void *ccp_irq_data;
+
+	unsigned int psp_irq;
+	irq_handler_t psp_irq_handler;
+	void *psp_irq_data;
+
+	void *ccp_data;
+	void *psp_data;
+};
+
+int sp_pci_init(void);
+void sp_pci_exit(void);
+
+int sp_platform_init(void);
+void sp_platform_exit(void);
+
+struct sp_device *sp_alloc_struct(struct device *dev);
+
+int sp_init(struct sp_device *sp);
+void sp_destroy(struct sp_device *sp);
+
+int sp_suspend(struct sp_device *sp);
+int sp_resume(struct sp_device *sp);
+int sp_restore(struct sp_device *sp);
+int sp_request_ccp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_ccp_irq(struct sp_device *sp, void *data);
+int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
+		       const char *name, void *data);
+void sp_free_psp_irq(struct sp_device *sp, void *data);
+struct sp_device *sp_get_psp_master_device(void);
+
+#ifdef CONFIG_CRYPTO_DEV_SP_CCP
+
+int ccp_dev_init(struct sp_device *sp);
+void ccp_dev_destroy(struct sp_device *sp);
+
+void ccp_dev_suspend(struct sp_device *sp);
+void ccp_dev_resume(struct sp_device *sp);
+
+#else	/* !CONFIG_CRYPTO_DEV_SP_CCP */
+
+static inline int ccp_dev_init(struct sp_device *sp)
+{
+	return 0;
+}
+static inline void ccp_dev_destroy(struct sp_device *sp) { }
+static inline void ccp_dev_suspend(struct sp_device *sp) { }
+static inline void ccp_dev_resume(struct sp_device *sp) { }
+#endif	/* CONFIG_CRYPTO_DEV_SP_CCP */
+
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP
+
+int psp_dev_init(struct sp_device *sp);
+void psp_pci_init(void);
+void psp_dev_destroy(struct sp_device *sp);
+void psp_pci_exit(void);
+int psp_restore(struct sp_device *sp);
+
+#else /* !CONFIG_CRYPTO_DEV_SP_PSP */
+
+static inline int psp_dev_init(struct sp_device *sp) { return 0; }
+static inline void psp_pci_init(void) { }
+static inline void psp_dev_destroy(struct sp_device *sp) { }
+static inline void psp_pci_exit(void) { }
+static inline int psp_restore(struct sp_device *sp) { return 0; }
+
+#endif /* CONFIG_CRYPTO_DEV_SP_PSP */
+
+#endif