Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Tianyu Lan <ltykernel@gmail.com>
To:     luto@kernel.org, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
        hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com,
        jgross@suse.com, tiala@microsoft.com, kirill@shutemov.name,
        jiangshan.ljs@antgroup.com, peterz@infradead.org,
        ashish.kalra@amd.com, srutherford@google.com,
        akpm@linux-foundation.org, anshuman.khandual@arm.com,
        pawan.kumar.gupta@linux.intel.com, adrian.hunter@intel.com,
        daniel.sneddon@linux.intel.com, alexander.shishkin@linux.intel.com,
        sandipan.das@amd.com, ray.huang@amd.com, brijesh.singh@amd.com,
        michael.roth@amd.com, thomas.lendacky@amd.com,
        venu.busireddy@oracle.com, sterritt@google.com,
        tony.luck@intel.com, samitolvanen@google.com, fenghua.yu@intel.com
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org
Subject: [RFC PATCH V2 10/18] drivers: hv: Decrypt percpu hvcall input arg page in sev-snp enlightened guest
Date:   Fri, 18 Nov 2022 22:46:24 -0500
Message-Id: <20221119034633.1728632-11-ltykernel@gmail.com>
In-Reply-To: <20221119034633.1728632-1-ltykernel@gmail.com>
References: <20221119034633.1728632-1-ltykernel@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Tianyu Lan <tiala@microsoft.com>

Hypervisor needs to access iput arg page and guest should decrypt
the page.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 drivers/hv/hv_common.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 2c6602571c47..c16961e686a0 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -21,6 +21,7 @@
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <linux/dma-map-ops.h>
+#include <linux/set_memory.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
@@ -125,6 +126,7 @@ int hv_common_cpu_init(unsigned int cpu)
 	u64 msr_vp_index;
 	gfp_t flags;
 	int pgcount = hv_root_partition ? 2 : 1;
+	int ret;
 
 	/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
 	flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
@@ -134,6 +136,16 @@ int hv_common_cpu_init(unsigned int cpu)
 	if (!(*inputarg))
 		return -ENOMEM;
 
+	if (hv_isolation_type_en_snp()) {
+		ret = set_memory_decrypted((unsigned long)*inputarg, 1);
+		if (ret) {
+			kfree(*inputarg);
+			return ret;
+		}
+
+		memset(*inputarg, 0x00, PAGE_SIZE);
+	}
+
 	if (hv_root_partition) {
 		outputarg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
 		*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
@@ -168,6 +180,9 @@ int hv_common_cpu_die(unsigned int cpu)
 
 	local_irq_restore(flags);
 
+	if (hv_isolation_type_en_snp())
+		set_memory_encrypted((unsigned long)mem, 1);
+
 	kfree(mem);
 
 	return 0;
-- 
2.25.1