- Add the necessary glue so that the kernel can run as a confidential

SEV-SNP vTOM guest on Hyper-V. A vTOM guest basically splits the
   address space in two parts: encrypted and unencrypted. The use case
   being running unmodified guests on the Hyper-V confidential computing
   hypervisor
 
 - Double-buffer messages between the guest and the hardware PSP device
   so that no partial buffers are copied back'n'forth and thus potential
   message integrity and leak attacks are possible
 
 - Name the return value the sev-guest driver returns when the hw PSP
   device hasn't been called, explicitly
 
 - Cleanups
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Merge tag 'x86_sev_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - Add the necessary glue so that the kernel can run as a confidential
   SEV-SNP vTOM guest on Hyper-V. A vTOM guest basically splits the
   address space in two parts: encrypted and unencrypted. The use case
   being running unmodified guests on the Hyper-V confidential computing
   hypervisor

 - Double-buffer messages between the guest and the hardware PSP device
   so that no partial buffers are copied back'n'forth and thus potential
   message integrity and leak attacks are possible

 - Name the return value the sev-guest driver returns when the hw PSP
   device hasn't been called, explicitly

 - Cleanups

* tag 'x86_sev_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hyperv: Change vTOM handling to use standard coco mechanisms
  init: Call mem_encrypt_init() after Hyper-V hypercall init is done
  x86/mm: Handle decryption/re-encryption of bss_decrypted consistently
  Drivers: hv: Explicitly request decrypted in vmap_pfn() calls
  x86/hyperv: Reorder code to facilitate future work
  x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM
  x86/sev: Change snp_guest_issue_request()'s fw_err argument
  virt/coco/sev-guest: Double-buffer messages
  crypto: ccp: Get rid of __sev_platform_init_locked()'s local function pointer
  crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL

Documentation/virt/coco/sev-guest.rst

@@ -37,11 +37,11 @@ along with a description:
       the return value.  General error numbers (-ENOMEM, -EINVAL)
       are not detailed, but errors with specific meanings are.
 
-The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device.
+The guest ioctl should be issued on a file descriptor of the /dev/sev-guest
-The ioctl accepts struct snp_user_guest_request. The input and output structure is
+device.  The ioctl accepts struct snp_user_guest_request. The input and
-specified through the req_data and resp_data field respectively. If the ioctl fails
+output structure is specified through the req_data and resp_data field
-to execute due to a firmware error, then fw_err code will be set otherwise the
+respectively. If the ioctl fails to execute due to a firmware error, then
-fw_err will be set to 0x00000000000000ff.
+the fw_error code will be set, otherwise fw_error will be set to -1.
 
 The firmware checks that the message sequence counter is one greater than
 the guests message sequence counter. If guest driver fails to increment message
@@ -57,8 +57,14 @@ counter (e.g. counter overflow), then -EIO will be returned.
                 __u64 req_data;
                 __u64 resp_data;
 
-                /* firmware error code on failure (see psp-sev.h) */
+                /* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */
-                __u64 fw_err;
+                union {
+                        __u64 exitinfo2;
+                        struct {
+                                __u32 fw_error;
+                                __u32 vmm_error;
+                        };
+                };
         };
 
 2.1 SNP_GET_REPORT

arch/x86/coco/core.c

@@ -29,6 +29,22 @@ static bool intel_cc_platform_has(enum cc_attr attr)
 	}
 }
 
+/*
+ * Handle the SEV-SNP vTOM case where sme_me_mask is zero, and
+ * the other levels of SME/SEV functionality, including C-bit
+ * based SEV-SNP, are not enabled.
+ */
+static __maybe_unused bool amd_cc_platform_vtom(enum cc_attr attr)
+{
+	switch (attr) {
+	case CC_ATTR_GUEST_MEM_ENCRYPT:
+	case CC_ATTR_MEM_ENCRYPT:
+		return true;
+	default:
+		return false;
+	}
+}
+
 /*
  * SME and SEV are very similar but they are not the same, so there are
  * times that the kernel will need to distinguish between SME and SEV. The
@@ -41,9 +57,14 @@ static bool intel_cc_platform_has(enum cc_attr attr)
  * up under SME the trampoline area cannot be encrypted, whereas under SEV
  * the trampoline area must be encrypted.
  */
+
 static bool amd_cc_platform_has(enum cc_attr attr)
 {
 #ifdef CONFIG_AMD_MEM_ENCRYPT
+
+	if (sev_status & MSR_AMD64_SNP_VTOM)
+		return amd_cc_platform_vtom(attr);
+
 	switch (attr) {
 	case CC_ATTR_MEM_ENCRYPT:
 		return sme_me_mask;
@@ -76,11 +97,6 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 #endif
 }
 
-static bool hyperv_cc_platform_has(enum cc_attr attr)
-{
-	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
-}
-
 bool cc_platform_has(enum cc_attr attr)
 {
 	switch (vendor) {
@@ -88,8 +104,6 @@ bool cc_platform_has(enum cc_attr attr)
 		return amd_cc_platform_has(attr);
 	case CC_VENDOR_INTEL:
 		return intel_cc_platform_has(attr);
-	case CC_VENDOR_HYPERV:
-		return hyperv_cc_platform_has(attr);
 	default:
 		return false;
 	}
@@ -103,11 +117,14 @@ u64 cc_mkenc(u64 val)
 	 * encryption status of the page.
 	 *
 	 * - for AMD, bit *set* means the page is encrypted
-	 * - for Intel *clear* means encrypted.
+	 * - for AMD with vTOM and for Intel, *clear* means encrypted
 	 */
 	switch (vendor) {
 	case CC_VENDOR_AMD:
-		return val | cc_mask;
+		if (sev_status & MSR_AMD64_SNP_VTOM)
+			return val & ~cc_mask;
+		else
+			return val | cc_mask;
 	case CC_VENDOR_INTEL:
 		return val & ~cc_mask;
 	default:
@@ -120,7 +137,10 @@ u64 cc_mkdec(u64 val)
 	/* See comment in cc_mkenc() */
 	switch (vendor) {
 	case CC_VENDOR_AMD:
-		return val & ~cc_mask;
+		if (sev_status & MSR_AMD64_SNP_VTOM)
+			return val | cc_mask;
+		else
+			return val & ~cc_mask;
 	case CC_VENDOR_INTEL:
 		return val | cc_mask;
 	default:

arch/x86/hyperv/hv_init.c

@@ -29,7 +29,6 @@
 #include <linux/syscore_ops.h>
 #include <clocksource/hyperv_timer.h>
 #include <linux/highmem.h>
-#include <linux/swiotlb.h>
 
 int hyperv_init_cpuhp;
 u64 hv_current_partition_id = ~0ull;
@@ -504,16 +503,6 @@ void __init hyperv_init(void)
 	/* Query the VMs extended capability once, so that it can be cached. */
 	hv_query_ext_cap(0);
 
-#ifdef CONFIG_SWIOTLB
-	/*
-	 * Swiotlb bounce buffer needs to be mapped in extra address
-	 * space. Map function doesn't work in the early place and so
-	 * call swiotlb_update_mem_attributes() here.
-	 */
-	if (hv_is_isolation_supported())
-		swiotlb_update_mem_attributes();
-#endif
-
 	return;
 
 clean_guest_os_id:

arch/x86/hyperv/ivm.c

@@ -13,6 +13,8 @@
 #include <asm/svm.h>
 #include <asm/sev.h>
 #include <asm/io.h>
+#include <asm/coco.h>
+#include <asm/mem_encrypt.h>
 #include <asm/mshyperv.h>
 #include <asm/hypervisor.h>
 
@@ -233,41 +235,6 @@ void hv_ghcb_msr_read(u64 msr, u64 *value)
 	local_irq_restore(flags);
 }
 EXPORT_SYMBOL_GPL(hv_ghcb_msr_read);
-#endif
-
-enum hv_isolation_type hv_get_isolation_type(void)
-{
-	if (!(ms_hyperv.priv_high & HV_ISOLATION))
-		return HV_ISOLATION_TYPE_NONE;
-	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
-}
-EXPORT_SYMBOL_GPL(hv_get_isolation_type);
-
-/*
- * hv_is_isolation_supported - Check system runs in the Hyper-V
- * isolation VM.
- */
-bool hv_is_isolation_supported(void)
-{
-	if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
-		return false;
-
-	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
-		return false;
-
-	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
-}
-
-DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
-
-/*
- * hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
- * isolation VM.
- */
-bool hv_isolation_type_snp(void)
-{
-	return static_branch_unlikely(&isolation_type_snp);
-}
 
 /*
  * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
@@ -320,27 +287,25 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
 }
 
 /*
- * hv_set_mem_host_visibility - Set specified memory visible to host.
+ * hv_vtom_set_host_visibility - Set specified memory visible to host.
  *
  * In Isolation VM, all guest memory is encrypted from host and guest
  * needs to set memory visible to host via hvcall before sharing memory
  * with host. This function works as wrap of hv_mark_gpa_visibility()
  * with memory base and size.
  */
-int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visible)
+static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
 {
-	enum hv_mem_host_visibility visibility = visible ?
+	enum hv_mem_host_visibility visibility = enc ?
-			VMBUS_PAGE_VISIBLE_READ_WRITE : VMBUS_PAGE_NOT_VISIBLE;
+			VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
 	u64 *pfn_array;
 	int ret = 0;
+	bool result = true;
 	int i, pfn;
 
-	if (!hv_is_isolation_supported() || !hv_hypercall_pg)
-		return 0;
-
 	pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
 	if (!pfn_array)
-		return -ENOMEM;
+		return false;
 
 	for (i = 0, pfn = 0; i < pagecount; i++) {
 		pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE);
@@ -349,17 +314,68 @@ int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visibl
 		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
 			ret = hv_mark_gpa_visibility(pfn, pfn_array,
 						     visibility);
-			if (ret)
+			if (ret) {
+				result = false;
 				goto err_free_pfn_array;
+			}
 			pfn = 0;
 		}
 	}
 
  err_free_pfn_array:
 	kfree(pfn_array);
-	return ret;
+	return result;
 }
 
+static bool hv_vtom_tlb_flush_required(bool private)
+{
+	return true;
+}
+
+static bool hv_vtom_cache_flush_required(void)
+{
+	return false;
+}
+
+static bool hv_is_private_mmio(u64 addr)
+{
+	/*
+	 * Hyper-V always provides a single IO-APIC in a guest VM.
+	 * When a paravisor is used, it is emulated by the paravisor
+	 * in the guest context and must be mapped private.
+	 */
+	if (addr >= HV_IOAPIC_BASE_ADDRESS &&
+	    addr < (HV_IOAPIC_BASE_ADDRESS + PAGE_SIZE))
+		return true;
+
+	/* Same with a vTPM */
+	if (addr >= VTPM_BASE_ADDRESS &&
+	    addr < (VTPM_BASE_ADDRESS + PAGE_SIZE))
+		return true;
+
+	return false;
+}
+
+void __init hv_vtom_init(void)
+{
+	/*
+	 * By design, a VM using vTOM doesn't see the SEV setting,
+	 * so SEV initialization is bypassed and sev_status isn't set.
+	 * Set it here to indicate a vTOM VM.
+	 */
+	sev_status = MSR_AMD64_SNP_VTOM;
+	cc_set_vendor(CC_VENDOR_AMD);
+	cc_set_mask(ms_hyperv.shared_gpa_boundary);
+	physical_mask &= ms_hyperv.shared_gpa_boundary - 1;
+
+	x86_platform.hyper.is_private_mmio = hv_is_private_mmio;
+	x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required;
+	x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
+	x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
+}
+
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
+
 /*
  * hv_map_memory - map memory to extra space in the AMD SEV-SNP Isolation VM.
  */
@@ -377,7 +393,7 @@ void *hv_map_memory(void *addr, unsigned long size)
 		pfns[i] = vmalloc_to_pfn(addr + i * PAGE_SIZE) +
 			(ms_hyperv.shared_gpa_boundary >> PAGE_SHIFT);
 
-	vaddr = vmap_pfn(pfns, size / PAGE_SIZE, PAGE_KERNEL_IO);
+	vaddr = vmap_pfn(pfns, size / PAGE_SIZE, pgprot_decrypted(PAGE_KERNEL));
 	kfree(pfns);
 
 	return vaddr;
@@ -387,3 +403,37 @@ void hv_unmap_memory(void *addr)
 {
 	vunmap(addr);
 }
+
+enum hv_isolation_type hv_get_isolation_type(void)
+{
+	if (!(ms_hyperv.priv_high & HV_ISOLATION))
+		return HV_ISOLATION_TYPE_NONE;
+	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
+}
+EXPORT_SYMBOL_GPL(hv_get_isolation_type);
+
+/*
+ * hv_is_isolation_supported - Check system runs in the Hyper-V
+ * isolation VM.
+ */
+bool hv_is_isolation_supported(void)
+{
+	if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
+		return false;
+
+	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
+		return false;
+
+	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
+}
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+
+/*
+ * hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
+ * isolation VM.
+ */
+bool hv_isolation_type_snp(void)
+{
+	return static_branch_unlikely(&isolation_type_snp);
+}

arch/x86/include/asm/coco.h

@@ -7,7 +7,6 @@
 enum cc_vendor {
 	CC_VENDOR_NONE,
 	CC_VENDOR_AMD,
-	CC_VENDOR_HYPERV,
 	CC_VENDOR_INTEL,
 };
 

arch/x86/include/asm/mem_encrypt.h

@@ -56,6 +56,7 @@ void __init sev_es_init_vc_handling(void);
 #else	/* !CONFIG_AMD_MEM_ENCRYPT */
 
 #define sme_me_mask	0ULL
+#define sev_status	0ULL
 
 static inline void __init sme_early_encrypt(resource_size_t paddr,
 					    unsigned long size) { }

arch/x86/include/asm/mshyperv.h

@@ -11,6 +11,14 @@
 #include <asm/paravirt.h>
 #include <asm/mshyperv.h>
 
+/*
+ * Hyper-V always provides a single IO-APIC at this MMIO address.
+ * Ideally, the value should be looked up in ACPI tables, but it
+ * is needed for mapping the IO-APIC early in boot on Confidential
+ * VMs, before ACPI functions can be used.
+ */
+#define HV_IOAPIC_BASE_ADDRESS 0xfec00000
+
 union hv_ghcb;
 
 DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
@@ -206,18 +214,19 @@ struct irq_domain *hv_create_pci_msi_domain(void);
 int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
 		struct hv_interrupt_entry *entry);
 int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
-int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 void hv_ghcb_msr_write(u64 msr, u64 value);
 void hv_ghcb_msr_read(u64 msr, u64 *value);
 bool hv_ghcb_negotiate_protocol(void);
 void hv_ghcb_terminate(unsigned int set, unsigned int reason);
+void hv_vtom_init(void);
 #else
 static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
 static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
 static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
 static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
+static inline void hv_vtom_init(void) {}
 #endif
 
 extern bool hv_isolation_type_snp(void);
@@ -259,11 +268,6 @@ static inline void hv_set_register(unsigned int reg, u64 value) { }
 static inline u64 hv_get_register(unsigned int reg) { return 0; }
 static inline void hv_set_non_nested_register(unsigned int reg, u64 value) { }
 static inline u64 hv_get_non_nested_register(unsigned int reg) { return 0; }
-static inline int hv_set_mem_host_visibility(unsigned long addr, int numpages,
-					     bool visible)
-{
-	return -1;
-}
 #endif /* CONFIG_HYPERV */
 
 

arch/x86/include/asm/sev-common.h

@@ -128,10 +128,6 @@ struct snp_psc_desc {
 	struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY];
 } __packed;
 
-/* Guest message request error codes */
-#define SNP_GUEST_REQ_INVALID_LEN	BIT_ULL(32)
-#define SNP_GUEST_REQ_ERR_BUSY		BIT_ULL(33)
-
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf

arch/x86/include/asm/sev.h

@@ -9,6 +9,8 @@
 #define __ASM_ENCRYPTED_STATE_H
 
 #include <linux/types.h>
+#include <linux/sev-guest.h>
+
 #include <asm/insn.h>
 #include <asm/sev-common.h>
 #include <asm/bootparam.h>
@@ -185,6 +187,9 @@ static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
 
 	return rc;
 }
+
+struct snp_guest_request_ioctl;
+
 void setup_ghcb(void);
 void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
 					 unsigned int npages);
@@ -196,7 +201,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
 void snp_set_wakeup_secondary_cpu(void);
 bool snp_init(struct boot_params *bp);
 void __init __noreturn snp_abort(void);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
 #else
 static inline void sev_es_ist_enter(struct pt_regs *regs) { }
 static inline void sev_es_ist_exit(void) { }
@@ -216,8 +221,7 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npag
 static inline void snp_set_wakeup_secondary_cpu(void) { }
 static inline bool snp_init(struct boot_params *bp) { return false; }
 static inline void snp_abort(void) { }
-static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input,
+static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
-					  unsigned long *fw_err)
 {
 	return -ENOTTY;
 }

arch/x86/include/asm/x86_init.h

@@ -259,11 +259,15 @@ struct x86_legacy_features {
  *				VMMCALL under SEV-ES.  Needs to return 'false'
  *				if the checks fail.  Called from the #VC
  *				exception handler.
+ * @is_private_mmio:		For CoCo VMs, must map MMIO address as private.
+ *				Used when device is emulated by a paravisor
+ *				layer in the VM context.
  */
 struct x86_hyper_runtime {
 	void (*pin_vcpu)(int cpu);
 	void (*sev_es_hcall_prepare)(struct ghcb *ghcb, struct pt_regs *regs);
 	bool (*sev_es_hcall_finish)(struct ghcb *ghcb, struct pt_regs *regs);
+	bool (*is_private_mmio)(u64 addr);
 };
 
 /**

arch/x86/kernel/apic/io_apic.c

@@ -66,6 +66,7 @@
 #include <asm/hw_irq.h>
 #include <asm/apic.h>
 #include <asm/pgtable.h>
+#include <asm/x86_init.h>
 
 #define	for_each_ioapic(idx)		\
 	for ((idx) = 0; (idx) < nr_ioapics; (idx)++)
@@ -2680,10 +2681,15 @@ static void io_apic_set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
 	pgprot_t flags = FIXMAP_PAGE_NOCACHE;
 
 	/*
-	 * Ensure fixmaps for IOAPIC MMIO respect memory encryption pgprot
+	 * Ensure fixmaps for IO-APIC MMIO respect memory encryption pgprot
 	 * bits, just like normal ioremap():
 	 */
-	flags = pgprot_decrypted(flags);
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
+		if (x86_platform.hyper.is_private_mmio(phys))
+			flags = pgprot_encrypted(flags);
+		else
+			flags = pgprot_decrypted(flags);
+	}
 
 	__set_fixmap(idx, phys, flags);
 }

arch/x86/kernel/cpu/mshyperv.c

@@ -33,7 +33,6 @@
 #include <asm/nmi.h>
 #include <clocksource/hyperv_timer.h>
 #include <asm/numa.h>
-#include <asm/coco.h>
 
 /* Is Linux running as the root partition? */
 bool hv_root_partition;
@@ -401,8 +400,10 @@ static void __init ms_hyperv_init_platform(void)
 	if (ms_hyperv.priv_high & HV_ISOLATION) {
 		ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
 		ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
-		ms_hyperv.shared_gpa_boundary =
+
-			BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
+		if (ms_hyperv.shared_gpa_boundary_active)
+			ms_hyperv.shared_gpa_boundary =
+				BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
 
 		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
@@ -413,11 +414,6 @@ static void __init ms_hyperv_init_platform(void)
 			swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
 #endif
 		}
-		/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
-		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
-				cc_set_vendor(CC_VENDOR_HYPERV);
-		}
 	}
 
 	if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
@@ -486,6 +482,9 @@ static void __init ms_hyperv_init_platform(void)
 	i8253_clear_counter_on_shutdown = false;
 
 #if IS_ENABLED(CONFIG_HYPERV)
+	if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
+	    (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP))
+		hv_vtom_init();
 	/*
 	 * Setup the hook to get control post apic initialization.
 	 */

arch/x86/kernel/sev.c

@@ -22,6 +22,8 @@
 #include <linux/efi.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
+#include <linux/psp-sev.h>
+#include <uapi/linux/sev-guest.h>
 
 #include <asm/cpu_entry_area.h>
 #include <asm/stacktrace.h>
@@ -2175,7 +2177,7 @@ static int __init init_sev_config(char *str)
 }
 __setup("sev=", init_sev_config);
 
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err)
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
 {
 	struct ghcb_state state;
 	struct es_em_ctxt ctxt;
@@ -2183,8 +2185,7 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned
 	struct ghcb *ghcb;
 	int ret;
 
-	if (!fw_err)
+	rio->exitinfo2 = SEV_RET_NO_FW_CALL;
-		return -EINVAL;
 
 	/*
 	 * __sev_get_ghcb() needs to run with IRQs disabled because it is using
@@ -2209,16 +2210,16 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned
 	if (ret)
 		goto e_put;
 
-	*fw_err = ghcb->save.sw_exit_info_2;
+	rio->exitinfo2 = ghcb->save.sw_exit_info_2;
-	switch (*fw_err) {
+	switch (rio->exitinfo2) {
 	case 0:
 		break;
 
-	case SNP_GUEST_REQ_ERR_BUSY:
+	case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY):
 		ret = -EAGAIN;
 		break;
 
-	case SNP_GUEST_REQ_INVALID_LEN:
+	case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN):
 		/* Number of expected pages are returned in RBX */
 		if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) {
 			input->data_npages = ghcb_get_rbx(ghcb);

arch/x86/kernel/x86_init.c

@@ -134,6 +134,7 @@ static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool
 static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return false; }
 static bool enc_tlb_flush_required_noop(bool enc) { return false; }
 static bool enc_cache_flush_required_noop(void) { return false; }
+static bool is_private_mmio_noop(u64 addr) {return false; }
 
 struct x86_platform_ops x86_platform __ro_after_init = {
 	.calibrate_cpu			= native_calibrate_cpu_early,
@@ -149,6 +150,7 @@ struct x86_platform_ops x86_platform __ro_after_init = {
 	.realmode_reserve		= reserve_real_mode,
 	.realmode_init			= init_real_mode,
 	.hyper.pin_vcpu			= x86_op_int_noop,
+	.hyper.is_private_mmio		= is_private_mmio_noop,
 
 	.guest = {
 		.enc_status_change_prepare = enc_status_change_prepare_noop,

arch/x86/mm/ioremap.c

@@ -116,6 +116,11 @@ static void __ioremap_check_other(resource_size_t addr, struct ioremap_desc *des
 	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
 		return;
 
+	if (x86_platform.hyper.is_private_mmio(addr)) {
+		desc->flags |= IORES_MAP_ENCRYPTED;
+		return;
+	}
+
 	if (!IS_ENABLED(CONFIG_EFI))
 		return;
 

arch/x86/mm/mem_encrypt_amd.c

@@ -513,10 +513,14 @@ void __init mem_encrypt_free_decrypted_mem(void)
 	npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
 
 	/*
-	 * The unused memory range was mapped decrypted, change the encryption
+	 * If the unused memory range was mapped decrypted, change the encryption
-	 * attribute from decrypted to encrypted before freeing it.
+	 * attribute from decrypted to encrypted before freeing it. Base the
+	 * re-encryption on the same condition used for the decryption in
+	 * sme_postprocess_startup(). Higher level abstractions, such as
+	 * CC_ATTR_MEM_ENCRYPT, aren't necessarily equivalent in a Hyper-V VM
+	 * using vTOM, where sme_me_mask is always zero.
 	 */
-	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
+	if (sme_me_mask) {
 		r = set_memory_encrypted(vaddr, npages);
 		if (r) {
 			pr_warn("failed to free unused decrypted pages\n");

arch/x86/mm/pat/set_memory.c

@@ -2175,9 +2175,6 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
 
 static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
 {
-	if (hv_is_isolation_supported())
-		return hv_set_mem_host_visibility(addr, numpages, !enc);
-
 	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return __set_memory_enc_pgtable(addr, numpages, enc);
 

drivers/crypto/ccp/sev-dev.c

@@ -442,12 +442,19 @@ static int __sev_init_ex_locked(int *error)
 	return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error);
 }
 
+static inline int __sev_do_init_locked(int *psp_ret)
+{
+	if (sev_init_ex_buffer)
+		return __sev_init_ex_locked(psp_ret);
+	else
+		return __sev_init_locked(psp_ret);
+}
+
 static int __sev_platform_init_locked(int *error)
 {
+	int rc = 0, psp_ret = SEV_RET_NO_FW_CALL;
 	struct psp_device *psp = psp_master;
 	struct sev_device *sev;
-	int rc = 0, psp_ret = -1;
-	int (*init_function)(int *error);
 
 	if (!psp || !psp->sev_data)
 		return -ENODEV;
@@ -458,15 +465,12 @@ static int __sev_platform_init_locked(int *error)
 		return 0;
 
 	if (sev_init_ex_buffer) {
-		init_function = __sev_init_ex_locked;
 		rc = sev_read_init_ex_file();
 		if (rc)
 			return rc;
-	} else {
-		init_function = __sev_init_locked;
 	}
 
-	rc = init_function(&psp_ret);
+	rc = __sev_do_init_locked(&psp_ret);
 	if (rc && psp_ret == SEV_RET_SECURE_DATA_INVALID) {
 		/*
 		 * Initialization command returned an integrity check failure
@@ -475,9 +479,11 @@ static int __sev_platform_init_locked(int *error)
 		 * initialization function should succeed by replacing the state
 		 * with a reset state.
 		 */
-		dev_err(sev->dev, "SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
+		dev_err(sev->dev,
-		rc = init_function(&psp_ret);
+"SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
+		rc = __sev_do_init_locked(&psp_ret);
 	}
+
 	if (error)
 		*error = psp_ret;
 

drivers/hv/ring_buffer.c

@@ -211,7 +211,7 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
 
 		ring_info->ring_buffer = (struct hv_ring_buffer *)
 			vmap_pfn(pfns_wraparound, page_cnt * 2 - 1,
-				 PAGE_KERNEL);
+				 pgprot_decrypted(PAGE_KERNEL));
 		kfree(pfns_wraparound);
 
 		if (!ring_info->ring_buffer)

drivers/hv/vmbus_drv.c

@@ -2156,7 +2156,6 @@ void vmbus_device_unregister(struct hv_device *device_obj)
  * VMBUS is an acpi enumerated device. Get the information we
  * need from DSDT.
  */
-#define VTPM_BASE_ADDRESS 0xfed40000
 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 {
 	resource_size_t start = 0;

drivers/virt/coco/sev-guest/sev-guest.c

@@ -46,7 +46,15 @@ struct snp_guest_dev {
 
 	void *certs_data;
 	struct snp_guest_crypto *crypto;
+	/* request and response are in unencrypted memory */
 	struct snp_guest_msg *request, *response;
+
+	/*
+	 * Avoid information leakage by double-buffering shared messages
+	 * in fields that are in regular encrypted memory.
+	 */
+	struct snp_guest_msg secret_request, secret_response;
+
 	struct snp_secrets_page_layout *layout;
 	struct snp_req_data input;
 	u32 *os_area_msg_seqno;
@@ -266,14 +274,17 @@ static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
 static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
 {
 	struct snp_guest_crypto *crypto = snp_dev->crypto;
-	struct snp_guest_msg *resp = snp_dev->response;
+	struct snp_guest_msg *resp = &snp_dev->secret_response;
-	struct snp_guest_msg *req = snp_dev->request;
+	struct snp_guest_msg *req = &snp_dev->secret_request;
 	struct snp_guest_msg_hdr *req_hdr = &req->hdr;
 	struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
 
 	dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
 		resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
 
+	/* Copy response from shared memory to encrypted memory. */
+	memcpy(resp, snp_dev->response, sizeof(*resp));
+
 	/* Verify that the sequence counter is incremented by 1 */
 	if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
 		return -EBADMSG;
@@ -297,7 +308,7 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
 static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
 			void *payload, size_t sz)
 {
-	struct snp_guest_msg *req = snp_dev->request;
+	struct snp_guest_msg *req = &snp_dev->secret_request;
 	struct snp_guest_msg_hdr *hdr = &req->hdr;
 
 	memset(req, 0, sizeof(*req));
@@ -321,11 +332,12 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
 	return __enc_payload(snp_dev, req, payload, sz);
 }
 
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+				  struct snp_guest_request_ioctl *rio)
 {
-	unsigned long err = 0xff, override_err = 0;
 	unsigned long req_start = jiffies;
 	unsigned int override_npages = 0;
+	u64 override_err = 0;
 	int rc;
 
 retry_request:
@@ -335,7 +347,7 @@ retry_request:
 	 * sequence number must be incremented or the VMPCK must be deleted to
 	 * prevent reuse of the IV.
 	 */
-	rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
+	rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio);
 	switch (rc) {
 	case -ENOSPC:
 		/*
@@ -353,7 +365,7 @@ retry_request:
 		 * request buffer size was too small and give the caller the
 		 * required buffer size.
 		 */
-		override_err	= SNP_GUEST_REQ_INVALID_LEN;
+		override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN);
 
 		/*
 		 * If this call to the firmware succeeds, the sequence number can
@@ -366,7 +378,7 @@ retry_request:
 		goto retry_request;
 
 	/*
-	 * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
+	 * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been
 	 * throttled. Retry in the driver to avoid returning and reusing the
 	 * message sequence number on a different message.
 	 */
@@ -387,27 +399,29 @@ retry_request:
 	 */
 	snp_inc_msg_seqno(snp_dev);
 
-	if (fw_err)
+	if (override_err) {
-		*fw_err = override_err ?: err;
+		rio->exitinfo2 = override_err;
+
+		/*
+		 * If an extended guest request was issued and the supplied certificate
+		 * buffer was not large enough, a standard guest request was issued to
+		 * prevent IV reuse. If the standard request was successful, return -EIO
+		 * back to the caller as would have originally been returned.
+		 */
+		if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
+			rc = -EIO;
+	}
 
 	if (override_npages)
 		snp_dev->input.data_npages = override_npages;
 
-	/*
-	 * If an extended guest request was issued and the supplied certificate
-	 * buffer was not large enough, a standard guest request was issued to
-	 * prevent IV reuse. If the standard request was successful, return -EIO
-	 * back to the caller as would have originally been returned.
-	 */
-	if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
-		return -EIO;
-
 	return rc;
 }
 
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
+static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
-				u8 type, void *req_buf, size_t req_sz, void *resp_buf,
+				struct snp_guest_request_ioctl *rio, u8 type,
-				u32 resp_sz, __u64 *fw_err)
+				void *req_buf, size_t req_sz, void *resp_buf,
+				u32 resp_sz)
 {
 	u64 seqno;
 	int rc;
@@ -417,19 +431,31 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
 	if (!seqno)
 		return -EIO;
 
+	/* Clear shared memory's response for the host to populate. */
 	memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
 
-	/* Encrypt the userspace provided payload */
+	/* Encrypt the userspace provided payload in snp_dev->secret_request. */
-	rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
+	rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz);
 	if (rc)
 		return rc;
 
-	rc = __handle_guest_request(snp_dev, exit_code, fw_err);
+	/*
+	 * Write the fully encrypted request to the shared unencrypted
+	 * request page.
+	 */
+	memcpy(snp_dev->request, &snp_dev->secret_request,
+	       sizeof(snp_dev->secret_request));
+
+	rc = __handle_guest_request(snp_dev, exit_code, rio);
 	if (rc) {
-		if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)
+		if (rc == -EIO &&
+		    rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
 			return rc;
 
-		dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err);
+		dev_alert(snp_dev->dev,
+			  "Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
+			  rc, rio->exitinfo2);
+
 		snp_disable_vmpck(snp_dev);
 		return rc;
 	}
@@ -469,9 +495,9 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
 	if (!resp)
 		return -ENOMEM;
 
-	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version,
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
 				  SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data,
-				  resp_len, &arg->fw_err);
+				  resp_len);
 	if (rc)
 		goto e_free;
 
@@ -509,9 +535,8 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
 	if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
 		return -EFAULT;
 
-	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version,
+	rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
-				  SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len,
+				  SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len);
-				  &arg->fw_err);
 	if (rc)
 		return rc;
 
@@ -571,12 +596,12 @@ cmd:
 		return -ENOMEM;
 
 	snp_dev->input.data_npages = npages;
-	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version,
+	ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
 				   SNP_MSG_REPORT_REQ, &req.data,
-				   sizeof(req.data), resp->data, resp_len, &arg->fw_err);
+				   sizeof(req.data), resp->data, resp_len);
 
 	/* If certs length is invalid then copy the returned length */
-	if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
+	if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
 		req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
 
 		if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
@@ -611,7 +636,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
 	if (copy_from_user(&input, argp, sizeof(input)))
 		return -EFAULT;
 
-	input.fw_err = 0xff;
+	input.exitinfo2 = 0xff;
 
 	/* Message version must be non-zero */
 	if (!input.msg_version)
@@ -642,7 +667,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
 
 	mutex_unlock(&snp_cmd_mutex);
 
-	if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
+	if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input)))
 		return -EFAULT;
 
 	return ret;

include/asm-generic/mshyperv.h

@@ -26,6 +26,8 @@
 #include <asm/ptrace.h>
 #include <asm/hyperv-tlfs.h>
 
+#define VTPM_BASE_ADDRESS 0xfed40000
+
 struct ms_hyperv_info {
 	u32 features;
 	u32 priv_high;

include/uapi/linux/psp-sev.h

@@ -36,6 +36,13 @@ enum {
  * SEV Firmware status code
  */
 typedef enum {
+	/*
+	 * This error code is not in the SEV spec. Its purpose is to convey that
+	 * there was an error that prevented the SEV firmware from being called.
+	 * The SEV API error codes are 16 bits, so the -1 value will not overlap
+	 * with possible values from the specification.
+	 */
+	SEV_RET_NO_FW_CALL = -1,
 	SEV_RET_SUCCESS = 0,
 	SEV_RET_INVALID_PLATFORM_STATE,
 	SEV_RET_INVALID_GUEST_STATE,

include/uapi/linux/sev-guest.h

@@ -52,8 +52,14 @@ struct snp_guest_request_ioctl {
 	__u64 req_data;
 	__u64 resp_data;
 
-	/* firmware error code on failure (see psp-sev.h) */
+	/* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */
-	__u64 fw_err;
+	union {
+		__u64 exitinfo2;
+		struct {
+			__u32 fw_error;
+			__u32 vmm_error;
+		};
+	};
 };
 
 struct snp_ext_report_req {
@@ -77,4 +83,12 @@ struct snp_ext_report_req {
 /* Get SNP extended report as defined in the GHCB specification version 2. */
 #define SNP_GET_EXT_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x2, struct snp_guest_request_ioctl)
 
+/* Guest message request EXIT_INFO_2 constants */
+#define SNP_GUEST_FW_ERR_MASK		GENMASK_ULL(31, 0)
+#define SNP_GUEST_VMM_ERR_SHIFT		32
+#define SNP_GUEST_VMM_ERR(x)		(((u64)x) << SNP_GUEST_VMM_ERR_SHIFT)
+
+#define SNP_GUEST_VMM_ERR_INVALID_LEN	1
+#define SNP_GUEST_VMM_ERR_BUSY		2
+
 #endif /* __UAPI_LINUX_SEV_GUEST_H_ */

init/main.c

@@ -1092,14 +1092,6 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	 */
 	locking_selftest();
 
-	/*
-	 * This needs to be called before any devices perform DMA
-	 * operations that might use the SWIOTLB bounce buffers. It will
-	 * mark the bounce buffers as decrypted so that their usage will
-	 * not cause "plain-text" data to be decrypted when accessed.
-	 */
-	mem_encrypt_init();
-
 #ifdef CONFIG_BLK_DEV_INITRD
 	if (initrd_start && !initrd_below_start_ok &&
 	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
@@ -1116,6 +1108,17 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 		late_time_init();
 	sched_clock_init();
 	calibrate_delay();
+
+	/*
+	 * This needs to be called before any devices perform DMA
+	 * operations that might use the SWIOTLB bounce buffers. It will
+	 * mark the bounce buffers as decrypted so that their usage will
+	 * not cause "plain-text" data to be decrypted when accessed. It
+	 * must be called after late_time_init() so that Hyper-V x86/x64
+	 * hypercalls work when the SWIOTLB bounce buffers are decrypted.
+	 */
+	mem_encrypt_init();
+
 	pid_idr_init();
 	anon_vma_init();
 #ifdef CONFIG_X86