linux-kernel - [PATCH v18 088/121] KVM: TDX: Handle vmentry failure for INTEL TD guest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <bb3248cc0ca1cac6071825b868879f703e970009.1705965635.git.isaku.yamahata@intel.com>
Date: Mon, 22 Jan 2024 15:54:04 -0800
From: isaku.yamahata@...el.com
To: kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: isaku.yamahata@...el.com,
	isaku.yamahata@...il.com,
	Paolo Bonzini <pbonzini@...hat.com>,
	erdemaktas@...gle.com,
	Sean Christopherson <seanjc@...gle.com>,
	Sagi Shahar <sagis@...gle.com>,
	Kai Huang <kai.huang@...el.com>,
	chen.bo@...el.com,
	hang.yuan@...el.com,
	tina.zhang@...el.com,
	Yao Yuan <yuan.yao@...el.com>
Subject: [PATCH v18 088/121] KVM: TDX: Handle vmentry failure for INTEL TD guest

From: Yao Yuan <yuan.yao@...el.com>

TDX module passes control back to VMM if it failed to vmentry for a TD, use
same exit reason to notify user space, align with VMX.
If VMM corrupted TD VMCS, machine check during entry can happens.  vm exit
reason will be EXIT_REASON_MCE_DURING_VMENTRY.  If VMM corrupted TD VMCS
with debug TD by TDH.VP.WR, the exit reason would be
EXIT_REASON_INVALID_STATE or EXIT_REASON_MSR_LOAD_FAIL.

Signed-off-by: Yao Yuan <yuan.yao@...el.com>
---
 arch/x86/kvm/vmx/tdx.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index eea36f990e17..cb4a8a8d8e1b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1365,6 +1365,28 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
 		goto unhandled_exit;
 	}
 
+	/*
+	 * When TDX module saw VMEXIT_REASON_FAILED_VMENTER_MC etc, TDH.VP.ENTER
+	 * returns with TDX_SUCCESS | exit_reason with failed_vmentry = 1.
+	 * Because TDX module maintains TD VMCS correctness, usually vmentry
+	 * failure shouldn't happen.  In some corner cases it can happen.  For
+	 * example
+	 * - machine check during entry: EXIT_REASON_MCE_DURING_VMENTRY
+	 * - TDH.VP.WR with debug TD.  VMM can corrupt TD VMCS
+	 *   - EXIT_REASON_INVALID_STATE
+	 *   - EXIT_REASON_MSR_LOAD_FAIL
+	 */
+	if (unlikely(exit_reason.failed_vmentry)) {
+		pr_err("TDExit: exit_reason 0x%016llx qualification=%016lx ext_qualification=%016lx\n",
+		       exit_reason.full, tdexit_exit_qual(vcpu), tdexit_ext_exit_qual(vcpu));
+		vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY;
+		vcpu->run->fail_entry.hardware_entry_failure_reason
+			= exit_reason.full;
+		vcpu->run->fail_entry.cpu = vcpu->arch.last_vmentry_cpu;
+
+		return 0;
+	}
+
 	WARN_ON_ONCE(fastpath != EXIT_FASTPATH_NONE);
 
 	switch (exit_reason.basic) {
-- 
2.25.1