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
Subject: [PATCH v5 28/34] x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user
Date: Mon, 6 Mar 2023 18:39:40 -0800 [thread overview]
Message-ID: <20230307023946.14516-29-xin3.li@intel.com> (raw)
In-Reply-To: <20230307023946.14516-1-xin3.li@intel.com>
If the stack frame contains an invalid user context (e.g. due to invalid SS,
a non-canonical RIP, etc.) the ERETU instruction will trap (#SS or #GP).
From a Linux point of view, this really should be considered a user space
failure, so use the standard fault fixup mechanism to intercept the fault,
fix up the exception frame, and redirect execution to fred_entrypoint_user.
The end result is that it appears just as if the hardware had taken the
exception immediately after completing the transition to user space.
Suggested-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/entry/entry_64_fred.S | 8 +++++--
arch/x86/include/asm/extable_fixup_types.h | 4 +++-
arch/x86/mm/extable.c | 28 ++++++++++++++++++++++
3 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/entry_64_fred.S b/arch/x86/entry/entry_64_fred.S
index 1fb765fd3871..027ef8f1e600 100644
--- a/arch/x86/entry/entry_64_fred.S
+++ b/arch/x86/entry/entry_64_fred.S
@@ -5,8 +5,10 @@
* The actual FRED entry points.
*/
#include <linux/linkage.h>
-#include <asm/errno.h>
+#include <asm/asm.h>
#include <asm/asm-offsets.h>
+#include <asm/errno.h>
+#include <asm/export.h>
#include <asm/fred.h>
#include "calling.h"
@@ -38,7 +40,9 @@ SYM_CODE_START_NOALIGN(fred_entrypoint_user)
call fred_entry_from_user
SYM_INNER_LABEL(fred_exit_user, SYM_L_GLOBAL)
FRED_EXIT
- ERETU
+1: ERETU
+
+ _ASM_EXTABLE_TYPE(1b, fred_entrypoint_user, EX_TYPE_ERETU)
SYM_CODE_END(fred_entrypoint_user)
/*
diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h
index 991e31cfde94..1585c798a02f 100644
--- a/arch/x86/include/asm/extable_fixup_types.h
+++ b/arch/x86/include/asm/extable_fixup_types.h
@@ -64,6 +64,8 @@
#define EX_TYPE_UCOPY_LEN4 (EX_TYPE_UCOPY_LEN | EX_DATA_IMM(4))
#define EX_TYPE_UCOPY_LEN8 (EX_TYPE_UCOPY_LEN | EX_DATA_IMM(8))
-#define EX_TYPE_ZEROPAD 20 /* longword load with zeropad on fault */
+#define EX_TYPE_ZEROPAD 20 /* longword load with zeropad on fault */
+
+#define EX_TYPE_ERETU 21
#endif
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 60814e110a54..88a2c419ce8b 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -6,6 +6,7 @@
#include <xen/xen.h>
#include <asm/fpu/api.h>
+#include <asm/fred.h>
#include <asm/sev.h>
#include <asm/traps.h>
#include <asm/kdebug.h>
@@ -195,6 +196,29 @@ static bool ex_handler_ucopy_len(const struct exception_table_entry *fixup,
return ex_handler_uaccess(fixup, regs, trapnr);
}
+#ifdef CONFIG_X86_FRED
+static bool ex_handler_eretu(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, unsigned long error_code)
+{
+ struct pt_regs *uregs = (struct pt_regs *)(regs->sp - offsetof(struct pt_regs, ip));
+ unsigned short ss = uregs->ss;
+ unsigned short cs = uregs->cs;
+
+ fred_info(uregs)->edata = fred_event_data(regs);
+ uregs->ssx = regs->ssx;
+ uregs->ss = ss;
+ uregs->csx = regs->csx;
+ uregs->current_stack_level = 0;
+ uregs->cs = cs;
+
+ /* Copy error code to uregs and adjust stack pointer accordingly */
+ uregs->orig_ax = error_code;
+ regs->sp -= 8;
+
+ return ex_handler_default(fixup, regs);
+}
+#endif
+
int ex_get_fixup_type(unsigned long ip)
{
const struct exception_table_entry *e = search_exception_tables(ip);
@@ -272,6 +296,10 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
return ex_handler_ucopy_len(e, regs, trapnr, reg, imm);
case EX_TYPE_ZEROPAD:
return ex_handler_zeropad(e, regs, fault_addr);
+#ifdef CONFIG_X86_FRED
+ case EX_TYPE_ERETU:
+ return ex_handler_eretu(e, regs, error_code);
+#endif
}
BUG();
}
--
2.34.1
next prev parent reply other threads:[~2023-03-07 3:07 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-07 2:39 [PATCH v5 00/34] x86: enable FRED for x86-64 Xin Li
2023-03-07 2:39 ` [PATCH v5 01/34] x86/traps: let common_interrupt() handle IRQ_MOVE_CLEANUP_VECTOR Xin Li
2023-03-07 2:39 ` [PATCH v5 02/34] x86/traps: add a system interrupt table for system interrupt dispatch Xin Li
2023-03-07 2:39 ` [PATCH v5 03/34] x86/traps: add install_system_interrupt_handler() Xin Li
2023-03-07 2:39 ` [PATCH v5 04/34] x86/traps: add external_interrupt() to dispatch external interrupts Xin Li
2023-03-20 15:36 ` Peter Zijlstra
2023-03-20 17:42 ` Peter Zijlstra
2023-03-20 23:47 ` Li, Xin3
2023-03-20 17:53 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 05/34] x86/traps: export external_interrupt() for VMX IRQ reinjection Xin Li
2023-03-22 17:52 ` Sean Christopherson
2023-03-22 22:38 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 06/34] x86/cpufeature: add the cpu feature bit for FRED Xin Li
2023-03-07 2:39 ` [PATCH v5 07/34] x86/opcode: add ERETU, ERETS instructions to x86-opcode-map Xin Li
2023-03-07 2:39 ` [PATCH v5 08/34] x86/objtool: teach objtool about ERETU and ERETS Xin Li
2023-03-07 2:39 ` [PATCH v5 09/34] x86/cpu: add X86_CR4_FRED macro Xin Li
2023-03-07 2:39 ` [PATCH v5 10/34] x86/fred: add Kconfig option for FRED (CONFIG_X86_FRED) Xin Li
2023-03-07 2:39 ` [PATCH v5 11/34] x86/fred: if CONFIG_X86_FRED is disabled, disable FRED support Xin Li
2023-03-07 2:39 ` [PATCH v5 12/34] x86/cpu: add MSR numbers for FRED configuration Xin Li
2023-03-07 2:39 ` [PATCH v5 13/34] x86/fred: header file for event types Xin Li
2023-03-07 2:39 ` [PATCH v5 14/34] x86/fred: header file with FRED definitions Xin Li
2023-03-07 2:39 ` [PATCH v5 15/34] x86/fred: make unions for the cs and ss fields in struct pt_regs Xin Li
2023-03-07 2:39 ` [PATCH v5 16/34] x86/fred: reserve space for the FRED stack frame Xin Li
2023-03-07 2:39 ` [PATCH v5 17/34] x86/fred: add a page fault entry stub for FRED Xin Li
2023-03-07 2:39 ` [PATCH v5 18/34] x86/fred: add a debug " Xin Li
2023-03-07 2:39 ` [PATCH v5 19/34] x86/fred: add a NMI " Xin Li
2023-03-07 2:39 ` [PATCH v5 20/34] x86/fred: add a machine check " Xin Li
2023-03-20 16:00 ` Peter Zijlstra
2023-03-21 0:04 ` Li, Xin3
2023-03-21 8:59 ` Peter Zijlstra
2023-03-21 16:38 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 21/34] x86/fred: FRED entry/exit and dispatch code Xin Li
2023-03-07 2:39 ` [PATCH v5 22/34] x86/fred: FRED initialization code Xin Li
2023-03-17 13:35 ` Lai Jiangshan
2023-03-17 21:32 ` H. Peter Anvin
2023-03-18 6:33 ` Lai Jiangshan
2023-03-20 16:49 ` Peter Zijlstra
2023-03-21 0:12 ` Li, Xin3
2023-03-21 1:02 ` andrew.cooper3
2023-03-21 7:49 ` Li, Xin3
2023-03-22 16:29 ` Dave Hansen
2023-03-22 2:22 ` Li, Xin3
2023-03-22 4:01 ` Dave Hansen
2023-03-22 5:40 ` Li, Xin3
2023-03-22 18:25 ` andrew.cooper3
2023-03-20 16:44 ` Peter Zijlstra
2023-03-21 0:13 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 23/34] x86/fred: update MSR_IA32_FRED_RSP0 during task switch Xin Li
2023-03-20 16:52 ` Peter Zijlstra
2023-03-20 23:54 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 24/34] x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is enabled Xin Li
2023-03-07 2:39 ` [PATCH v5 25/34] x86/fred: disallow the swapgs instruction " Xin Li
2023-03-20 16:54 ` Peter Zijlstra
2023-03-20 17:58 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 26/34] x86/fred: no ESPFIX needed " Xin Li
2023-03-07 2:39 ` [PATCH v5 27/34] x86/fred: allow single-step trap and NMI when starting a new thread Xin Li
2023-03-07 2:39 ` Xin Li [this message]
2023-03-17 9:39 ` [PATCH v5 28/34] x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user Lai Jiangshan
2023-03-17 9:55 ` andrew.cooper3
2023-03-17 13:02 ` Lai Jiangshan
2023-03-17 21:23 ` H. Peter Anvin
2023-03-17 21:00 ` H. Peter Anvin
2023-03-18 7:55 ` Li, Xin3
2023-03-07 2:39 ` [PATCH v5 29/34] x86/ia32: do not modify the DPL bits for a null selector Xin Li
2023-03-07 2:39 ` [PATCH v5 30/34] x86/fred: allow FRED systems to use interrupt vectors 0x10-0x1f Xin Li
2023-03-07 2:39 ` [PATCH v5 31/34] x86/fred: allow dynamic stack frame size Xin Li
2023-03-07 2:39 ` [PATCH v5 32/34] x86/fred: disable FRED by default in its early stage Xin Li
2023-03-07 2:39 ` [PATCH v5 33/34] KVM: x86/vmx: call external_interrupt() to handle IRQ in IRQ caused VM exits Xin Li
2023-03-22 17:57 ` Sean Christopherson
2023-03-07 2:39 ` [PATCH v5 34/34] KVM: x86/vmx: execute "int $2" to handle NMI in NMI caused VM exits when FRED is enabled Xin Li
2023-03-07 22:00 ` Li, Xin3
2023-03-22 17:49 ` Sean Christopherson
2023-03-22 23:03 ` andrew.cooper3
2023-03-22 23:42 ` Sean Christopherson
2023-03-23 0:26 ` Li, Xin3
2023-03-24 17:45 ` Li, Xin3
2023-03-22 23:43 ` Li, Xin3
2023-03-11 9:58 ` [PATCH v5 00/34] x86: enable FRED for x86-64 Kang, Shan
2023-03-11 21:29 ` Li, Xin3
2023-03-20 7:40 ` Kang, Shan
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