Received-SPF: pass (google.com: domain of linux-kernel+bounces-187460-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C
From: Ravi Bangoria <ravi.bangoria@amd.com>
To: <seanjc@google.com>, <pbonzini@redhat.com>, <nikunj.dadhania@amd.com>
CC: <ravi.bangoria@amd.com>, <thomas.lendacky@amd.com>, <tglx@linutronix.de>,
	<mingo@redhat.com>, <bp@alien8.de>, <dave.hansen@linux.intel.com>,
	<x86@kernel.org>, <hpa@zytor.com>, <michael.roth@amd.com>,
	<pankaj.gupta@amd.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <santosh.shukla@amd.com>
Subject: [PATCH v3 0/3] KVM: SEV-ES: Fix KVM_{GET|SET}_MSRS and LBRV handling
Date: Thu, 23 May 2024 12:18:25 +0000
Message-ID: <20240523121828.808-1-ravi.bangoria@amd.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 May 2024 12:19:03.3807
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 6be3b846-84e2-461a-b52f-08dc7b2288ce
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource:
	BN1PEPF00004681.namprd03.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4152

Fix couple of interrelated issues:

o KVM currently allows userspace to access MSRs even after the VMSA is
  encrypted. This can result into issues if MSR update has side effects on
  VM configuration. Patch 1 fixes that by preventing KVM_{GET|SET}_MSRS
  for SEV-ES guests once VMSA is encrypted.

o As documented in APM, LBR Virtualization must be enabled for SEV-ES
  guests. However, KVM currently enables LBRV unconditionally without
  checking feature bit, which is wrong. Patch 2 prevents SEV-ES guests
  when LBRV support is missing.

o Although LBRV is enabled for SEV-ES guests, MSR_IA32_DEBUGCTLMSR was
  still intercepted. This can crash SEV-ES guest if used inadvertently.
  Patch 3 fixes it.

Patches prepared on kvm/next (6f627b425378)

v2: https://lore.kernel.org/r/20240416050338.517-1-ravi.bangoria@amd.com
v2->v3: Fix all affiliated issues along with fixing MSR_IA32_DEBUGCTLMSR
   interception:
 - Block KVM_{GET|SET}_MSRS for SEV-ES guests post VMSA encryption (new)
 - Block SEV-ES guest creation when LBRV is disabled/not supported (new)
 - Move LBRV enablement code after VMSA encryption to avoid a scenario
   where LBRV can be disabled inadvertently through MSR_IA32_DEBUGCTLMSR
   write. (new)
 - Removed all 'Reviewed-by' since the code has changed quite a bit.

Nikunj A Dadhania (1):
  KVM: SEV-ES: Prevent MSR access post VMSA encryption

Ravi Bangoria (2):
  KVM: SEV-ES: Disallow SEV-ES guests when X86_FEATURE_LBRV is absent
  KVM: SEV-ES: Fix LBRV code

 arch/x86/kvm/svm/sev.c | 21 +++++++++++++++------
 arch/x86/kvm/svm/svm.c | 42 ++++++++++++++++++++++++++++++++----------
 arch/x86/kvm/svm/svm.h |  7 ++++---
 3 files changed, 51 insertions(+), 19 deletions(-)

-- 
2.45.1