From: Tom Lendacky <thomas.lendacky@amd.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH] x86/virtio: Have SEV guests enforce restricted virtio memory access
Date: Thu, 4 Mar 2021 16:40:11 -0600 [thread overview]
Message-ID: <b46e0211f77ca1831f11132f969d470a6ffc9267.1614897610.git.thomas.lendacky@amd.com> (raw)
From: Tom Lendacky <thomas.lendacky@amd.com>
An SEV guest requires that virtio devices use the DMA API to allow the
hypervisor to successfully access guest memory as needed.
The VIRTIO_F_VERSION_1 and VIRTIO_F_ACCESS_PLATFORM features tell virtio
to use the DMA API. Add arch_has_restricted_virtio_memory_access() for
x86, to fail the device probe if these features have not been set for the
device when running as an SEV guest.
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/Kconfig | 1 +
arch/x86/mm/mem_encrypt.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2792879d398e..e80e7268d2c6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1518,6 +1518,7 @@ config AMD_MEM_ENCRYPT
select ARCH_USE_MEMREMAP_PROT
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
select INSTRUCTION_DECODER
+ select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
help
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 4b01f7dbaf30..667283f3dcfa 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -484,3 +484,8 @@ void __init mem_encrypt_init(void)
print_mem_encrypt_feature_info();
}
+int arch_has_restricted_virtio_memory_access(void)
+{
+ return sev_active();
+}
+EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);
--
2.30.0
reply other threads:[~2021-03-04 22:40 UTC|newest]
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