Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Ashish Kalra <Ashish.Kalra@amd.com>
To:     pbonzini@redhat.com
Cc:     tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
        joro@8bytes.org, bp@suse.de, thomas.lendacky@amd.com,
        x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        rientjes@google.com, srutherford@google.com, luto@kernel.org,
        brijesh.singh@amd.com
Subject: [PATCH v6 10/14] mm: x86: Invoke hypercall when page encryption status is changed
Date:   Mon, 30 Mar 2020 06:22:38 +0000
Message-Id: <05c9015fb13b25c07a84d5638a7cd65a8c136cf0.1585548051.git.ashish.kalra@amd.com>
In-Reply-To: <cover.1585548051.git.ashish.kalra@amd.com>
References: <cover.1585548051.git.ashish.kalra@amd.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from ashkalra_ubuntu_server.amd.com (165.204.77.1) by DM5PR17CA0056.namprd17.prod.outlook.com (2603:10b6:3:13f::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2856.20 via Frontend Transport; Mon, 30 Mar 2020 06:22:47 +0000
X-Mailer: git-send-email 2.17.1
X-Originating-IP: [165.204.77.1]
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-HT: Tenant
X-MS-Office365-Filtering-Correlation-Id: 45bcbddb-a2fa-42b9-ee3a-08d7d472c472
X-MS-TrafficTypeDiagnostic: DM5PR12MB1692:|DM5PR12MB1692:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <DM5PR12MB1692A4F72FA245D3E07F51A18ECB0@DM5PR12MB1692.namprd12.prod.outlook.com>
X-MS-Oob-TLC-OOBClassifiers: OLM:5516;
X-Forefront-PRVS: 0358535363
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM5PR12MB1386.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFTY:;SFS:(10009020)(4636009)(346002)(136003)(366004)(39860400002)(396003)(376002)(66556008)(86362001)(66476007)(478600001)(2616005)(956004)(81166006)(52116002)(8676002)(66574012)(81156014)(6916009)(7696005)(8936002)(5660300002)(6666004)(6486002)(16526019)(186003)(26005)(66946007)(316002)(7416002)(2906002)(4326008)(36756003)(136400200001);DIR:OUT;SFP:1101;
Received-SPF: None (protection.outlook.com: amd.com does not designate
 permitted sender hosts)
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: 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
X-MS-Exchange-AntiSpam-MessageData: 9CcZZBDIqjddi5h8evanL3yT7hJbjAoP5zv1gOQWja2toFXIwl3DuJKKuwEuCQklORjea/Et1yKfEvPByTF2H1k/I/YEV84CJgOflmPFgKAH2vTNdQl6dYCdJEDF1iIwxwJMUSUYMGh+3G9lon0Ifg==
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 45bcbddb-a2fa-42b9-ee3a-08d7d472c472
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Mar 2020 06:22:48.5020
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 4fW6TlEg3ZoF5xd3OVV0umy8ATwQeo8FTLZQnx6dL49sF46kT7mxKnlOs9c92dYj2Vet0zmnoR7jEIf/cVnK+A==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR12MB1692
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Brijesh Singh <Brijesh.Singh@amd.com>

Invoke a hypercall when a memory region is changed from encrypted ->
decrypted and vice versa. Hypervisor need to know the page encryption
status during the guest migration.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 arch/x86/include/asm/paravirt.h       | 10 +++++
 arch/x86/include/asm/paravirt_types.h |  2 +
 arch/x86/kernel/paravirt.c            |  1 +
 arch/x86/mm/mem_encrypt.c             | 57 ++++++++++++++++++++++++++-
 arch/x86/mm/pat/set_memory.c          |  7 ++++
 5 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 694d8daf4983..8127b9c141bf 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -78,6 +78,12 @@ static inline void paravirt_arch_exit_mmap(struct mm_struct *mm)
 	PVOP_VCALL1(mmu.exit_mmap, mm);
 }
 
+static inline void page_encryption_changed(unsigned long vaddr, int npages,
+						bool enc)
+{
+	PVOP_VCALL3(mmu.page_encryption_changed, vaddr, npages, enc);
+}
+
 #ifdef CONFIG_PARAVIRT_XXL
 static inline void load_sp0(unsigned long sp0)
 {
@@ -946,6 +952,10 @@ static inline void paravirt_arch_dup_mmap(struct mm_struct *oldmm,
 static inline void paravirt_arch_exit_mmap(struct mm_struct *mm)
 {
 }
+
+static inline void page_encryption_changed(unsigned long vaddr, int npages, bool enc)
+{
+}
 #endif
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_X86_PARAVIRT_H */
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 732f62e04ddb..03bfd515c59c 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -215,6 +215,8 @@ struct pv_mmu_ops {
 
 	/* Hook for intercepting the destruction of an mm_struct. */
 	void (*exit_mmap)(struct mm_struct *mm);
+	void (*page_encryption_changed)(unsigned long vaddr, int npages,
+					bool enc);
 
 #ifdef CONFIG_PARAVIRT_XXL
 	struct paravirt_callee_save read_cr2;
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index c131ba4e70ef..840c02b23aeb 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -367,6 +367,7 @@ struct paravirt_patch_template pv_ops = {
 			(void (*)(struct mmu_gather *, void *))tlb_remove_page,
 
 	.mmu.exit_mmap		= paravirt_nop,
+	.mmu.page_encryption_changed	= paravirt_nop,
 
 #ifdef CONFIG_PARAVIRT_XXL
 	.mmu.read_cr2		= __PV_IS_CALLEE_SAVE(native_read_cr2),
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index f4bd4b431ba1..c9800fa811f6 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/bitops.h>
 #include <linux/dma-mapping.h>
+#include <linux/kvm_para.h>
 
 #include <asm/tlbflush.h>
 #include <asm/fixmap.h>
@@ -29,6 +30,7 @@
 #include <asm/processor-flags.h>
 #include <asm/msr.h>
 #include <asm/cmdline.h>
+#include <asm/kvm_para.h>
 
 #include "mm_internal.h"
 
@@ -196,6 +198,47 @@ void __init sme_early_init(void)
 		swiotlb_force = SWIOTLB_FORCE;
 }
 
+static void set_memory_enc_dec_hypercall(unsigned long vaddr, int npages,
+					bool enc)
+{
+	unsigned long sz = npages << PAGE_SHIFT;
+	unsigned long vaddr_end, vaddr_next;
+
+	vaddr_end = vaddr + sz;
+
+	for (; vaddr < vaddr_end; vaddr = vaddr_next) {
+		int psize, pmask, level;
+		unsigned long pfn;
+		pte_t *kpte;
+
+		kpte = lookup_address(vaddr, &level);
+		if (!kpte || pte_none(*kpte))
+			return;
+
+		switch (level) {
+		case PG_LEVEL_4K:
+			pfn = pte_pfn(*kpte);
+			break;
+		case PG_LEVEL_2M:
+			pfn = pmd_pfn(*(pmd_t *)kpte);
+			break;
+		case PG_LEVEL_1G:
+			pfn = pud_pfn(*(pud_t *)kpte);
+			break;
+		default:
+			return;
+		}
+
+		psize = page_level_size(level);
+		pmask = page_level_mask(level);
+
+		kvm_sev_hypercall3(KVM_HC_PAGE_ENC_STATUS,
+				   pfn << PAGE_SHIFT, psize >> PAGE_SHIFT, enc);
+
+		vaddr_next = (vaddr & pmask) + psize;
+	}
+}
+
 static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
 {
 	pgprot_t old_prot, new_prot;
@@ -253,12 +296,13 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
 static int __init early_set_memory_enc_dec(unsigned long vaddr,
 					   unsigned long size, bool enc)
 {
-	unsigned long vaddr_end, vaddr_next;
+	unsigned long vaddr_end, vaddr_next, start;
 	unsigned long psize, pmask;
 	int split_page_size_mask;
 	int level, ret;
 	pte_t *kpte;
 
+	start = vaddr;
 	vaddr_next = vaddr;
 	vaddr_end = vaddr + size;
 
@@ -313,6 +357,8 @@ static int __init early_set_memory_enc_dec(unsigned long vaddr,
 
 	ret = 0;
 
+	set_memory_enc_dec_hypercall(start, PAGE_ALIGN(size) >> PAGE_SHIFT,
+					enc);
 out:
 	__flush_tlb_all();
 	return ret;
@@ -451,6 +497,15 @@ void __init mem_encrypt_init(void)
 	if (sev_active())
 		static_branch_enable(&sev_enable_key);
 
+#ifdef CONFIG_PARAVIRT
+	/*
+	 * With SEV, we need to make a hypercall when page encryption state is
+	 * changed.
+	 */
+	if (sev_active())
+		pv_ops.mmu.page_encryption_changed = set_memory_enc_dec_hypercall;
+#endif
+
 	pr_info("AMD %s active\n",
 		sev_active() ? "Secure Encrypted Virtualization (SEV)"
 			     : "Secure Memory Encryption (SME)");
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index c4aedd00c1ba..86b7804129fc 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -26,6 +26,7 @@
 #include <asm/proto.h>
 #include <asm/memtype.h>
 #include <asm/set_memory.h>
+#include <asm/paravirt.h>
 
 #include "../mm_internal.h"
 
@@ -1987,6 +1988,12 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
 	 */
 	cpa_flush(&cpa, 0);
 
+	/* Notify hypervisor that a given memory range is mapped encrypted
+	 * or decrypted. The hypervisor will use this information during the
+	 * VM migration.
+	 */
+	page_encryption_changed(addr, numpages, enc);
+
 	return ret;
 }
 
-- 
2.17.1