Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest abstractionn

[Borislav Petkov <bp@alien8.de>]

From f1e9f051c86b09fe660f49b0307bc7c6cec5e6f4 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Thu, 3 Jun 2021 20:03:31 +0200
Subject: Convert sme_active()

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 9c80c68d75b5..1bb9f22629fc 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -50,7 +50,6 @@ void __init mem_encrypt_free_decrypted_mem(void);
 void __init mem_encrypt_init(void);
 
 void __init sev_es_init_vc_handling(void);
-bool sme_active(void);
 bool sev_active(void);
 bool sev_es_active(void);
 
@@ -75,7 +74,6 @@ static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
 static inline void __init sme_enable(struct boot_params *bp) { }
 
 static inline void sev_es_init_vc_handling(void) { }
-static inline bool sme_active(void) { return false; }
 static inline bool sev_active(void) { return false; }
 static inline bool sev_es_active(void) { return false; }
 
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index c078b0d3ab0e..1d88232146ab 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -387,7 +387,7 @@ void machine_kexec(struct kimage *image)
 				       (unsigned long)page_list,
 				       image->start,
 				       image->preserve_context,
-				       sme_active());
+				       protected_guest_has(VM_HOST_MEM_ENCRYPT));
 
 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index c2cfa5e7c152..ce6f2b9a05c7 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -49,7 +49,7 @@ int __init pci_swiotlb_detect_4gb(void)
 	 * buffers are allocated and used for devices that do not support
 	 * the addressing range required for the encryption mask.
 	 */
-	if (sme_active())
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		swiotlb = 1;
 
 	return swiotlb;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 01a224fdb897..3aa2658ced52 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1409,6 +1409,11 @@ bool sev_protected_guest_has(unsigned long flag)
 	case VM_MEM_ENCRYPT:
 	case VM_MEM_ENCRYPT_ACTIVE:
 		return true;
+	case VM_HOST_MEM_ENCRYPT:
+		return sme_me_mask && !sev_active();
+	default:
+		WARN_ON_ONCE(1);
+		return false;
 	}
 
 	return false;
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 667bba74e4c8..50ed2a768844 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -703,7 +703,7 @@ bool arch_memremap_can_ram_remap(resource_size_t phys_addr, unsigned long size,
 	if (flags & MEMREMAP_DEC)
 		return false;
 
-	if (sme_active()) {
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT)) {
 		if (memremap_is_setup_data(phys_addr, size) ||
 		    memremap_is_efi_data(phys_addr, size))
 			return false;
@@ -729,7 +729,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr,
 
 	encrypted_prot = true;
 
-	if (sme_active()) {
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT)) {
 		if (early_memremap_is_setup_data(phys_addr, size) ||
 		    memremap_is_efi_data(phys_addr, size))
 			encrypted_prot = false;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 49d11bb6e02a..9b0cdac895ca 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -145,7 +145,7 @@ void __init sme_unmap_bootdata(char *real_mode_data)
 	struct boot_params *boot_data;
 	unsigned long cmdline_paddr;
 
-	if (!sme_active())
+	if (!protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		return;
 
 	/* Get the command line address before unmapping the real_mode_data */
@@ -165,7 +165,7 @@ void __init sme_map_bootdata(char *real_mode_data)
 	struct boot_params *boot_data;
 	unsigned long cmdline_paddr;
 
-	if (!sme_active())
+	if (!protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		return;
 
 	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
@@ -365,7 +365,7 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
 /*
  * 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
- * sme_active() and sev_active() functions are used for this.  When a
+ * protected_guest_has(VM_HOST_MEM_ENCRYPT) and sev_active() functions are used for this.  When a
  * distinction isn't needed, the mem_encrypt_active() function can be used.
  *
  * The trampoline code is a good example for this requirement.  Before
@@ -378,11 +378,6 @@ bool sev_active(void)
 {
 	return sev_status & MSR_AMD64_SEV_ENABLED;
 }
-
-bool sme_active(void)
-{
-	return sme_me_mask && !sev_active();
-}
 EXPORT_SYMBOL_GPL(sev_active);
 
 /* Needs to be called from non-instrumentable code */
@@ -405,7 +400,7 @@ bool amd_force_dma_unencrypted(struct device *dev)
 	 * device does not support DMA to addresses that include the
 	 * encryption mask.
 	 */
-	if (sme_active()) {
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT)) {
 		u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
 		u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
 						dev->bus_dma_limit);
@@ -446,7 +441,7 @@ static void print_mem_encrypt_feature_info(void)
 	pr_info("AMD Memory Encryption Features active:");
 
 	/* Secure Memory Encryption */
-	if (sme_active()) {
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT)) {
 		/*
 		 * SME is mutually exclusive with any of the SEV
 		 * features below.
diff --git a/arch/x86/mm/mem_encrypt_common.c b/arch/x86/mm/mem_encrypt_common.c
index da94fc2e9b56..286357956762 100644
--- a/arch/x86/mm/mem_encrypt_common.c
+++ b/arch/x86/mm/mem_encrypt_common.c
@@ -15,7 +15,7 @@
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)
 {
-	if (sev_active() || sme_active())
+	if (sev_active() || protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		return amd_force_dma_unencrypted(dev);
 
 	if (protected_guest_has(VM_MEM_ENCRYPT))
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index a9639f663d25..a92b49aa0d73 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -30,6 +30,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/mem_encrypt.h>
+#include <linux/protected_guest.h>
 
 #include <asm/setup.h>
 #include <asm/sections.h>
@@ -287,7 +288,7 @@ void __init sme_encrypt_kernel(struct boot_params *bp)
 	unsigned long pgtable_area_len;
 	unsigned long decrypted_base;
 
-	if (!sme_active())
+	if (!protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		return;
 
 	/*
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 2e1c1bec0f9e..7f9a708986a3 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -42,7 +42,7 @@ void __init reserve_real_mode(void)
 static void sme_sev_setup_real_mode(struct trampoline_header *th)
 {
 #ifdef CONFIG_AMD_MEM_ENCRYPT
-	if (sme_active())
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		th->flags |= TH_FLAGS_SME_ACTIVE;
 
 	if (sev_es_active()) {
@@ -79,7 +79,7 @@ static void __init setup_real_mode(void)
 	 * decrypted memory in order to bring up other processors
 	 * successfully. This is not needed for SEV.
 	 */
-	if (sme_active())
+	if (protected_guest_has(VM_HOST_MEM_ENCRYPT))
 		set_memory_decrypted((unsigned long)base, size >> PAGE_SHIFT);
 
 	memcpy(base, real_mode_blob, size);
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index d006724f4dc2..3c2365f13cc3 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -965,7 +965,7 @@ static bool copy_device_table(void)
 		pr_err("The address of old device table is above 4G, not trustworthy!\n");
 		return false;
 	}
-	old_devtb = (sme_active() && is_kdump_kernel())
+	old_devtb = (protected_guest_has(VM_HOST_MEM_ENCRYPT) && is_kdump_kernel())
 		    ? (__force void *)ioremap_encrypted(old_devtb_phys,
 							dev_table_size)
 		    : memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);
@@ -3022,7 +3022,7 @@ static int __init amd_iommu_init(void)
 
 static bool amd_iommu_sme_check(void)
 {
-	if (!sme_active() || (boot_cpu_data.x86 != 0x17))
+	if (!protected_guest_has(VM_HOST_MEM_ENCRYPT) || (boot_cpu_data.x86 != 0x17))
 		return true;
 
 	/* For Fam17h, a specific level of support is required */

-- 
Regards/Gruss,
    Boris.

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