From: Xin Li <xin3.li@intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org,
andrew.cooper3@citrix.com, seanjc@google.com,
pbonzini@redhat.com, ravi.v.shankar@intel.com,
jiangshanlai@gmail.com, shan.kang@intel.com
Subject: [PATCH v6 06/33] x86/cpufeature: add the cpu feature bit for FRED
Date: Mon, 27 Mar 2023 00:58:11 -0700 [thread overview]
Message-ID: <20230327075838.5403-7-xin3.li@intel.com> (raw)
In-Reply-To: <20230327075838.5403-1-xin3.li@intel.com>
From: "H. Peter Anvin (Intel)" <hpa@zytor.com>
Add the CPU feature bit for FRED (Flexible Return and Event Delivery).
The Intel flexible return and event delivery (FRED) architecture defines simple
new transitions that change privilege level (ring transitions). The FRED
architecture was designed with the following goals:
1) Improve overall performance and response time by replacing event delivery
through the interrupt descriptor table (IDT event delivery) and event return by
the IRET instruction with lower latency transitions.
2) Improve software robustness by ensuring that event delivery establishes the
full supervisor context and that event return establishes the full user context.
The new transitions defined by the FRED architecture are FRED event delivery and,
for returning from events, two FRED return instructions. FRED event delivery can
effect a transition from ring 3 to ring 0, but it is used also to deliver events
incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to
ring 3, while the other (ERETS) returns while remaining in ring 0.
Search for the latest FRED spec in most search engines with this search pattern:
site:intel.com FRED (flexible return and event delivery) specification
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
arch/x86/include/asm/cpufeatures.h | 1 +
tools/arch/x86/include/asm/cpufeatures.h | 1 +
2 files changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 73c9672c123b..1fa444478d33 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -318,6 +318,7 @@
#define X86_FEATURE_FZRM (12*32+10) /* "" Fast zero-length REP MOVSB */
#define X86_FEATURE_FSRS (12*32+11) /* "" Fast short REP STOSB */
#define X86_FEATURE_FSRC (12*32+12) /* "" Fast short REP {CMPSB,SCASB} */
+#define X86_FEATURE_FRED (12*32+17) /* Flexible Return and Event Delivery */
#define X86_FEATURE_LKGS (12*32+18) /* "" Load "kernel" (userspace) GS */
#define X86_FEATURE_AMX_FP16 (12*32+21) /* "" AMX fp16 Support */
#define X86_FEATURE_AVX_IFMA (12*32+23) /* "" Support for VPMADD52[H,L]UQ */
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index b89005819cd5..e9064f4a011a 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -312,6 +312,7 @@
#define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
#define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */
#define X86_FEATURE_CMPCCXADD (12*32+ 7) /* "" CMPccXADD instructions */
+#define X86_FEATURE_FRED (12*32+17) /* Flexible Return and Event Delivery */
#define X86_FEATURE_LKGS (12*32+18) /* "" Load "kernel" (userspace) GS */
#define X86_FEATURE_AMX_FP16 (12*32+21) /* "" AMX fp16 Support */
#define X86_FEATURE_AVX_IFMA (12*32+23) /* "" Support for VPMADD52[H,L]UQ */
--
2.34.1
next prev parent reply other threads:[~2023-03-27 8:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 7:58 [PATCH v6 00/33] x86: enable FRED for x86-64 Xin Li
2023-03-27 7:58 ` [PATCH v6 01/33] x86/traps: let common_interrupt() handle IRQ_MOVE_CLEANUP_VECTOR Xin Li
2023-03-27 7:58 ` [PATCH v6 02/33] x86/fred: make unions for the cs and ss fields in struct pt_regs Xin Li
2023-03-27 7:58 ` [PATCH v6 03/33] x86/traps: add a system interrupt table for system interrupt dispatch Xin Li
2023-03-27 7:58 ` [PATCH v6 04/33] x86/traps: add install_system_interrupt_handler() Xin Li
2023-03-27 7:58 ` [PATCH v6 05/33] x86/traps: add external_interrupt() to dispatch external interrupts Xin Li
2023-03-27 7:58 ` Xin Li [this message]
2023-03-27 7:58 ` [PATCH v6 07/33] x86/opcode: add ERETU, ERETS instructions to x86-opcode-map Xin Li
2023-03-27 7:58 ` [PATCH v6 08/33] x86/objtool: teach objtool about ERETU and ERETS Xin Li
2023-03-27 7:58 ` [PATCH v6 09/33] x86/cpu: add X86_CR4_FRED macro Xin Li
2023-03-27 7:58 ` [PATCH v6 10/33] x86/fred: add Kconfig option for FRED (CONFIG_X86_FRED) Xin Li
2023-03-27 7:58 ` [PATCH v6 11/33] x86/fred: if CONFIG_X86_FRED is disabled, disable FRED support Xin Li
2023-03-27 7:58 ` [PATCH v6 12/33] x86/cpu: add MSR numbers for FRED configuration Xin Li
2023-03-27 7:58 ` [PATCH v6 13/33] x86/fred: header file for event types Xin Li
2023-03-27 7:58 ` [PATCH v6 14/33] x86/fred: header file with FRED definitions Xin Li
2023-03-27 7:58 ` [PATCH v6 15/33] x86/fred: reserve space for the FRED stack frame Xin Li
2023-03-27 7:58 ` [PATCH v6 16/33] x86/fred: add a page fault entry stub for FRED Xin Li
2023-03-27 7:58 ` [PATCH v6 17/33] x86/fred: add a debug " Xin Li
2023-03-27 7:58 ` [PATCH v6 18/33] x86/fred: add a NMI " Xin Li
2023-03-27 7:58 ` [PATCH v6 19/33] x86/fred: add a machine check " Xin Li
2023-03-27 7:58 ` [PATCH v6 20/33] x86/fred: FRED entry/exit and dispatch code Xin Li
2023-03-27 7:58 ` [PATCH v6 21/33] x86/fred: FRED initialization code Xin Li
2023-03-27 7:58 ` [PATCH v6 22/33] x86/fred: update MSR_IA32_FRED_RSP0 during task switch Xin Li
2023-03-27 7:58 ` [PATCH v6 23/33] x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is enabled Xin Li
2023-03-27 7:58 ` [PATCH v6 24/33] x86/fred: disallow the swapgs instruction " Xin Li
2023-03-27 7:58 ` [PATCH v6 25/33] x86/fred: no ESPFIX needed " Xin Li
2023-03-27 7:58 ` [PATCH v6 26/33] x86/fred: allow single-step trap and NMI when starting a new thread Xin Li
2023-03-27 7:58 ` [PATCH v6 27/33] x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user Xin Li
2023-03-31 8:03 ` Lai Jiangshan
2023-04-01 8:12 ` Li, Xin3
2023-03-27 7:58 ` [PATCH v6 28/33] x86/ia32: do not modify the DPL bits for a null selector Xin Li
2023-03-27 7:58 ` [PATCH v6 29/33] x86/fred: allow FRED systems to use interrupt vectors 0x10-0x1f Xin Li
2023-03-27 7:58 ` [PATCH v6 30/33] x86/fred: allow dynamic stack frame size Xin Li
2023-03-27 7:58 ` [PATCH v6 31/33] x86/fred: BUG() when ERETU with %rsp not equal to that when the ring 3 event was just delivered Xin Li
2023-03-27 7:58 ` [PATCH v6 32/33] x86/fred: disable FRED by default in its early stage Xin Li
2023-03-27 7:58 ` [PATCH v6 33/33] KVM: x86/vmx: refactor VMX_DO_EVENT_IRQOFF to generate FRED stack frames Xin Li
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