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From: Ross Philipson <ross.philipson@oracle.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-doc@vger.kernel.org
Cc: ross.philipson@oracle.com, dpsmith@apertussolutions.com,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	hpa@zytor.com, trenchboot-devel@googlegroups.com
Subject: [RFC PATCH 11/12] kexec: Secure Launch kexec SEXIT support
Date: Wed, 25 Mar 2020 15:43:16 -0400
Message-ID: <20200325194317.526492-12-ross.philipson@oracle.com> (raw)
In-Reply-To: <20200325194317.526492-1-ross.philipson@oracle.com>

Prior to running the next kernel via kexec, the Secure Launch code
closes down private SMX resources and does an SEXIT. This allows the
next kernel to start normally without any issues starting the APs etc.

Signed-off-by: Ross Philipson <ross.philipson@oracle.com>
---
 arch/x86/kernel/slaunch.c | 65 +++++++++++++++++++++++++++++++++++++++
 kernel/kexec_core.c       |  3 ++
 2 files changed, 68 insertions(+)

diff --git a/arch/x86/kernel/slaunch.c b/arch/x86/kernel/slaunch.c
index fea15b0e36b7..516964408fe5 100644
--- a/arch/x86/kernel/slaunch.c
+++ b/arch/x86/kernel/slaunch.c
@@ -633,3 +633,68 @@ static void __exit slaunch_exit(void)
 late_initcall(slaunch_late_init);
 
 __exitcall(slaunch_exit);
+
+static inline void txt_getsec_sexit(void)
+{
+	asm volatile (".byte 0x0f,0x37\n"
+		      : : "a" (SMX_X86_GETSEC_SEXIT));
+}
+
+void slaunch_sexit(void)
+{
+	void __iomem *config;
+	u64 one = 1, val;
+
+	if (!(slaunch_get_flags() & (SL_FLAG_ACTIVE|SL_FLAG_ARCH_TXT)))
+		return;
+
+	if (smp_processor_id() != 0) {
+		pr_err("Error TXT SEXIT must be called on CPU 0\n");
+		return;
+	}
+
+	config = ioremap(TXT_PRIV_CONFIG_REGS_BASE, TXT_NR_CONFIG_PAGES *
+			 PAGE_SIZE);
+	if (!config) {
+		pr_err("Error SEXIT failed to ioremap TXT private reqs\n");
+		return;
+	}
+
+	/* Clear secrets bit for SEXIT */
+	memcpy_toio(config + TXT_CR_CMD_NO_SECRETS, &one, sizeof(u64));
+	memcpy_fromio(&val, config + TXT_CR_E2STS, sizeof(u64));
+
+	/* Unlock memory configurations */
+	memcpy_toio(config + TXT_CR_CMD_UNLOCK_MEM_CONFIG, &one, sizeof(u64));
+	memcpy_fromio(&val, config + TXT_CR_E2STS, sizeof(u64));
+
+	/* Close the TXT private register space */
+	memcpy_fromio(&val, config + TXT_CR_E2STS, sizeof(u64));
+	memcpy_toio(config + TXT_CR_CMD_CLOSE_PRIVATE, &one, sizeof(u64));
+
+	/*
+	 * Calls to iounmap are not being done because of the state of the
+	 * system this late in the kexec process. Local IRQs are disabled and
+	 * iounmap causes a TLB flush which in turn causes a warning. Leaving
+	 * thse mappings is not an issue since the next kernel is going to
+	 * completely re-setup memory management.
+	 */
+
+	/* Map public registers and do a final read fence */
+	config = ioremap(TXT_PUB_CONFIG_REGS_BASE, TXT_NR_CONFIG_PAGES *
+			 PAGE_SIZE);
+	if (!config) {
+		pr_err("Error SEXIT failed to ioremap TXT public reqs\n");
+		return;
+	}
+
+	memcpy_fromio(&val, config + TXT_CR_E2STS, sizeof(u64));
+
+	/* Disable SMX mode */
+	cr4_set_bits(X86_CR4_SMXE);
+
+	/* Do the SEXIT SMX operation */
+	txt_getsec_sexit();
+
+	pr_emerg("TXT SEXIT complete.");
+}
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 15d70a90b50d..08105eeebf90 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -37,6 +37,7 @@
 #include <linux/compiler.h>
 #include <linux/hugetlb.h>
 #include <linux/frame.h>
+#include <linux/slaunch.h>
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -1173,6 +1174,8 @@ int kernel_kexec(void)
 		cpu_hotplug_enable();
 		pr_emerg("Starting new kernel\n");
 		machine_shutdown();
+
+		slaunch_sexit();
 	}
 
 	machine_kexec(kexec_image);
-- 
2.25.1


  parent reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 19:43 [RFC PATCH 00/12] x86: Trenchboot secure late launch Linux kernel support Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 01/12] x86: Secure Launch Kconfig Ross Philipson
2020-03-26 18:06   ` Daniel Kiper
2020-03-26 19:42     ` Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 02/12] x86: Secure Launch main header file Ross Philipson
2020-03-26 19:00   ` Daniel Kiper
2020-03-25 19:43 ` [RFC PATCH 03/12] x86: Add early SHA support for Secure Launch early measurements Ross Philipson
2020-03-26  3:44   ` Andy Lutomirski
2020-03-26 22:49     ` Daniel P. Smith
2020-03-25 19:43 ` [RFC PATCH 04/12] x86: Add early TPM TIS/CRB interface support for Secure Launch Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 05/12] x86: Add early TPM1.2/TPM2.0 " Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 06/12] x86: Add early general TPM " Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 07/12] x86: Secure Launch kernel early boot stub Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 08/12] x86: Secure Launch kernel late " Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 09/12] x86: Secure Launch SMP bringup support Ross Philipson
2020-03-25 19:43 ` [RFC PATCH 10/12] x86: Secure Launch adding event log securityfs Ross Philipson
2020-03-25 20:21   ` Matthew Garrett
2020-03-25 21:43     ` Daniel P. Smith
2020-03-25 19:43 ` Ross Philipson [this message]
2020-03-25 19:43 ` [RFC PATCH 12/12] tpm: Allow locality 2 to be set when initializing the TPM for Secure Launch Ross Philipson
2020-03-25 20:29 ` [RFC PATCH 00/12] x86: Trenchboot secure late launch Linux kernel support Matthew Garrett
2020-03-25 22:51   ` Andy Lutomirski
2020-03-26 20:50     ` Daniel P. Smith
2020-03-26 23:13       ` Andy Lutomirski
2020-05-11 19:00         ` Daniel P. Smith
2020-03-26 13:40   ` Daniel Kiper
2020-03-26 20:19     ` Matthew Garrett
2020-03-26 20:33       ` Andy Lutomirski
2020-03-26 20:40         ` Matthew Garrett
2020-03-26 20:59           ` Daniel P. Smith
2020-03-26 21:07           ` Andy Lutomirski
2020-03-26 21:28             ` Matthew Garrett
2020-03-26 22:52               ` Andy Lutomirski
2020-03-26 22:59                 ` Matthew Garrett
2020-03-26 23:04                   ` Andy Lutomirski
2020-03-27  0:01                     ` Daniel P. Smith
2020-03-26 23:50                 ` Daniel P. Smith
2020-05-11 19:00       ` Daniel P. Smith
2020-03-26 20:50   ` Daniel P. Smith
2020-03-26 20:54     ` Matthew Garrett
2020-03-26 22:37       ` Daniel P. Smith
2020-03-26 22:41         ` Matthew Garrett
2020-03-26 23:55           ` Daniel P. Smith

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