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From:   Tianyu Lan <ltykernel@gmail.com>
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Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org
Subject: [RFC PATCH V3 02/16] x86/hyperv: Decrypt hv vp assist page in sev-snp enlightened guest
Date:   Sat, 21 Jan 2023 21:45:52 -0500
Message-Id: <20230122024607.788454-3-ltykernel@gmail.com>
In-Reply-To: <20230122024607.788454-1-ltykernel@gmail.com>
References: <20230122024607.788454-1-ltykernel@gmail.com>
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From: Tianyu Lan <tiala@microsoft.com>

hv vp assist page is shared between sev snp guest and hyperv. Decrypt
the page when use it.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
 arch/x86/hyperv/hv_init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a5f9474f08e1..24154c1ee12b 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -29,6 +29,7 @@
 #include <linux/syscore_ops.h>
 #include <clocksource/hyperv_timer.h>
 #include <linux/highmem.h>
+#include <linux/set_memory.h>
 
 int hyperv_init_cpuhp;
 u64 hv_current_partition_id = ~0ull;
@@ -113,6 +114,11 @@ static int hv_cpu_init(unsigned int cpu)
 
 	}
 	if (!WARN_ON(!(*hvp))) {
+		if (hv_isolation_type_en_snp()) {
+			WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
+			memset(*hvp, 0, PAGE_SIZE);
+		}
+
 		msr.enable = 1;
 		wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 	}
-- 
2.25.1