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From: Kuppuswamy Sathyanarayanan  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>
Cc: Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 08/11] x86/tdx: Add HLT support for TDX guest
Date: Fri, 18 Jun 2021 15:57:52 -0700	[thread overview]
Message-ID: <20210618225755.662725-9-sathyanarayanan.kuppuswamy@linux.intel.com> (raw)
In-Reply-To: <20210618225755.662725-1-sathyanarayanan.kuppuswamy@linux.intel.com>

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

Per Guest-Host-Communication Interface (GHCI) for Intel Trust
Domain Extensions (Intel TDX) specification, sec 3.8,
TDVMCALL[Instruction.HLT] provides HLT operation. Use it to implement
halt() and safe_halt() paravirtualization calls.

The same TDX hypercall is used to handle #VE exception due to
EXIT_REASON_HLT.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
 arch/x86/kernel/tdx.c | 51 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index 21d0c9e78b0c..1ce528f8fc95 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -7,6 +7,7 @@
 #include <linux/protected_guest.h>
 
 #include <asm/tdx.h>
+#include <asm/vmx.h>
 
 /* TDX Module call Leaf IDs */
 #define TDINFO				1
@@ -80,6 +81,33 @@ static void tdg_get_info(void)
 	td_info.attributes = out.rdx;
 }
 
+static __cpuidle void tdg_halt(void)
+{
+	u64 ret;
+
+	ret = _tdx_hypercall(EXIT_REASON_HLT, irqs_disabled(), 0, 0, 0, NULL);
+
+	/* It should never fail */
+	BUG_ON(ret);
+}
+
+static __cpuidle void tdg_safe_halt(void)
+{
+	u64 ret;
+
+	/*
+	 * Enable interrupts next to the TDVMCALL to avoid
+	 * performance degradation.
+	 */
+	local_irq_enable();
+
+	/* IRQ is enabled, So set R12 as 0 */
+	ret = _tdx_hypercall(EXIT_REASON_HLT, 0, 0, 0, 0, NULL);
+
+	/* It should never fail */
+	BUG_ON(ret);
+}
+
 unsigned long tdg_get_ve_info(struct ve_info *ve)
 {
 	u64 ret;
@@ -106,13 +134,19 @@ unsigned long tdg_get_ve_info(struct ve_info *ve)
 int tdg_handle_virtualization_exception(struct pt_regs *regs,
 					struct ve_info *ve)
 {
-	/*
-	 * TODO: Add handler support for various #VE exit
-	 * reasons. It will be added by other patches in
-	 * the series.
-	 */
-	pr_warn("Unexpected #VE: %lld\n", ve->exit_reason);
-	return -EFAULT;
+	switch (ve->exit_reason) {
+	case EXIT_REASON_HLT:
+		tdg_halt();
+		break;
+	default:
+		pr_warn("Unexpected #VE: %lld\n", ve->exit_reason);
+		return -EFAULT;
+	}
+
+	/* After successful #VE handling, move the IP */
+	regs->ip += ve->instr_len;
+
+	return 0;
 }
 
 void __init tdx_early_init(void)
@@ -124,5 +158,8 @@ void __init tdx_early_init(void)
 
 	tdg_get_info();
 
+	pv_ops.irq.safe_halt = tdg_safe_halt;
+	pv_ops.irq.halt = tdg_halt;
+
 	pr_info("Guest initialized\n");
 }
-- 
2.25.1


  parent reply	other threads:[~2021-06-18 22:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 22:57 [PATCH v3 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-06-19 11:59   ` Juergen Gross
2021-06-19 17:11     ` Kuppuswamy, Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 03/11] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-06-18 23:39   ` Borislav Petkov
2021-06-19  0:13     ` Kuppuswamy, Sathyanarayanan
2021-06-19  6:38       ` Borislav Petkov
2021-07-15 11:56   ` Xiaoyao Li
2021-07-19  5:10     ` Kuppuswamy, Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 04/11] x86: Introduce generic protected guest abstraction Kuppuswamy Sathyanarayanan
2021-06-24 15:01   ` Borislav Petkov
2021-06-24 17:58     ` Kuppuswamy, Sathyanarayanan
2021-06-28 17:52   ` Tom Lendacky
2021-06-28 18:59     ` Tom Lendacky
2021-06-28 19:14     ` Kuppuswamy, Sathyanarayanan
2021-06-29 19:47       ` Tom Lendacky
2021-06-18 22:57 ` [PATCH v3 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 06/11] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 07/11] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` Kuppuswamy Sathyanarayanan [this message]
2021-06-18 22:57 ` [PATCH v3 09/11] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 10/11] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-18 22:57 ` [PATCH v3 11/11] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-06-30 23:22 ` [PATCH v3 00/11] Add TDX Guest Support (Initial support) Sathyanarayanan Kuppuswamy Natarajan

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