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, 95 insertions, 0 deletions

diff --git a/arch/powerpc/boot/ppcboot.h b/arch/powerpc/boot/ppcboot.h
new file mode 100644
index 000000000..90c8f452f
--- /dev/null
+++ b/arch/powerpc/boot/ppcboot.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * This interface is used for compatibility with old U-boots *ONLY*.
+ * Please do not imitate or extend this.
+ */
+
+/*
+ * (C) Copyright 2000, 2001
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ */
+
+#ifndef __PPCBOOT_H__
+#define __PPCBOOT_H__
+
+/*
+ * Board information passed to kernel from PPCBoot
+ *
+ * include/asm-ppc/ppcboot.h
+ */
+
+#include "types.h"
+
+typedef struct bd_info {
+	unsigned long	bi_memstart;	/* start of DRAM memory */
+	unsigned long	bi_memsize;	/* size	 of DRAM memory in bytes */
+	unsigned long	bi_flashstart;	/* start of FLASH memory */
+	unsigned long	bi_flashsize;	/* size	 of FLASH memory */
+	unsigned long	bi_flashoffset; /* reserved area for startup monitor */
+	unsigned long	bi_sramstart;	/* start of SRAM memory */
+	unsigned long	bi_sramsize;	/* size	 of SRAM memory */
+#if defined(TARGET_8xx) || defined(TARGET_CPM2) || defined(TARGET_85xx) ||\
+	defined(TARGET_83xx) || defined(TARGET_86xx)
+	unsigned long	bi_immr_base;	/* base of IMMR register */
+#endif
+#if defined(TARGET_PPC_MPC52xx)
+	unsigned long   bi_mbar_base;   /* base of internal registers */
+#endif
+	unsigned long	bi_bootflags;	/* boot / reboot flag (for LynxOS) */
+	unsigned long	bi_ip_addr;	/* IP Address */
+	unsigned char	bi_enetaddr[6];	/* Ethernet address */
+	unsigned short	bi_ethspeed;	/* Ethernet speed in Mbps */
+	unsigned long	bi_intfreq;	/* Internal Freq, in MHz */
+	unsigned long	bi_busfreq;	/* Bus Freq, in MHz */
+#if defined(TARGET_CPM2)
+	unsigned long	bi_cpmfreq;	/* CPM_CLK Freq, in MHz */
+	unsigned long	bi_brgfreq;	/* BRG_CLK Freq, in MHz */
+	unsigned long	bi_sccfreq;	/* SCC_CLK Freq, in MHz */
+	unsigned long	bi_vco;		/* VCO Out from PLL, in MHz */
+#endif
+#if defined(TARGET_PPC_MPC52xx)
+	unsigned long   bi_ipbfreq;     /* IPB Bus Freq, in MHz */
+	unsigned long   bi_pcifreq;     /* PCI Bus Freq, in MHz */
+#endif
+	unsigned long	bi_baudrate;	/* Console Baudrate */
+#if defined(TARGET_4xx)
+	unsigned char	bi_s_version[4];	/* Version of this structure */
+	unsigned char	bi_r_version[32];	/* Version of the ROM (IBM) */
+	unsigned int	bi_procfreq;	/* CPU (Internal) Freq, in Hz */
+	unsigned int	bi_plb_busfreq;	/* PLB Bus speed, in Hz */
+	unsigned int	bi_pci_busfreq;	/* PCI Bus speed, in Hz */
+	unsigned char	bi_pci_enetaddr[6];	/* PCI Ethernet MAC address */
+#endif
+#if defined(TARGET_HYMOD)
+	hymod_conf_t	bi_hymod_conf;	/* hymod configuration information */
+#endif
+#if defined(TARGET_EVB64260) || defined(TARGET_44x) || \
+	defined(TARGET_85xx) ||	defined(TARGET_83xx) || defined(TARGET_HAS_ETH1)
+	/* second onboard ethernet port */
+	unsigned char	bi_enet1addr[6];
+#define HAVE_ENET1ADDR
+#endif
+#if defined(TARGET_EVB64260) || defined(TARGET_440GX) || \
+    defined(TARGET_85xx) || defined(TARGET_HAS_ETH2)
+	/* third onboard ethernet ports */
+	unsigned char	bi_enet2addr[6];
+#define HAVE_ENET2ADDR
+#endif
+#if defined(TARGET_440GX) || defined(TARGET_HAS_ETH3)
+	/* fourth onboard ethernet ports */
+	unsigned char	bi_enet3addr[6];
+#define HAVE_ENET3ADDR
+#endif
+#if defined(TARGET_4xx)
+	unsigned int	bi_opbfreq;		/* OB clock in Hz */
+	int		bi_iic_fast[2];		/* Use fast i2c mode */
+#endif
+#if defined(TARGET_440GX)
+	int		bi_phynum[4];		/* phy mapping */
+	int		bi_phymode[4];		/* phy mode */
+#endif
+} bd_t;
+
+#define bi_tbfreq	bi_intfreq
+
+#endif	/* __PPCBOOT_H__ */