x86/kvm: Use bounce buffers for KVM memory protection

Mirror SEV, use SWIOTLB always if KVM memory protection is enabled. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
0day-ci · Oct 20, 2020 · 0bdb6c3 · 0bdb6c3
1 parent 466d697
commit 0bdb6c3
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Showing 5 changed files with 28 additions and 22 deletions.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
@@ -806,6 +806,7 @@ config KVM_GUEST
 	select ARCH_CPUIDLE_HALTPOLL
 	select X86_HV_CALLBACK_VECTOR
 	select X86_MEM_ENCRYPT_COMMON
+	select SWIOTLB
 	default y
 	help
 	  This option enables various optimizations for running under the KVM

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
@@ -26,6 +26,7 @@
 #include <linux/kprobes.h>
 #include <linux/nmi.h>
 #include <linux/swait.h>
+#include <linux/swiotlb.h>
 #include <asm/timer.h>
 #include <asm/cpu.h>
 #include <asm/traps.h>
@@ -759,6 +760,7 @@ static void __init kvm_init_platform(void)
 		pr_info("KVM memory protection enabled\n");
 		mem_protected = true;
 		setup_force_cpu_cap(X86_FEATURE_KVM_MEM_PROTECTED);
+		swiotlb_force = SWIOTLB_FORCE;
 	}
 }
 

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
@@ -13,6 +13,7 @@
 #include <asm/dma.h>
 #include <asm/xen/swiotlb-xen.h>
 #include <asm/iommu_table.h>
+#include <asm/kvm_para.h>
 
 int swiotlb __read_mostly;
 
@@ -49,7 +50,7 @@ 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 (sme_active() || kvm_mem_protected())
 		swiotlb = 1;
 
 	return swiotlb;

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
@@ -369,24 +369,3 @@ void __init mem_encrypt_free_decrypted_mem(void)
 
 	free_init_pages("unused decrypted", vaddr, vaddr_end);
 }
-
-/* Architecture __weak replacement functions */
-void __init mem_encrypt_init(void)
-{
-	if (!sme_me_mask)
-		return;
-
-	/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
-	swiotlb_update_mem_attributes();
-
-	/*
-	 * With SEV, we need to unroll the rep string I/O instructions.
-	 */
-	if (sev_active())
-		static_branch_enable(&sev_enable_key);
-
-	pr_info("AMD %s active\n",
-		sev_active() ? "Secure Encrypted Virtualization (SEV)"
-			     : "Secure Memory Encryption (SME)");
-}
-
diff --git a/arch/x86/mm/mem_encrypt_common.c b/arch/x86/mm/mem_encrypt_common.c
@@ -37,3 +37,26 @@ bool force_dma_unencrypted(struct device *dev)
 
 	return false;
 }
+
+void __init mem_encrypt_init(void)
+{
+	if (!sme_me_mask && !kvm_mem_protected())
+		return;
+
+	/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
+	swiotlb_update_mem_attributes();
+
+	/*
+	 * With SEV, we need to unroll the rep string I/O instructions.
+	 */
+	if (sev_active())
+		static_branch_enable(&sev_enable_key);
+
+	if (sme_me_mask) {
+		pr_info("AMD %s active\n",
+			sev_active() ? "Secure Encrypted Virtualization (SEV)"
+			: "Secure Memory Encryption (SME)");
+	} else {
+		pr_info("KVM memory protection enabled\n");
+	}
+}