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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>,
	"Wei Liu" <wei.liu2@citrix.com>,
	"Jan Beulich" <JBeulich@suse.com>
Subject: [PATCH 6/7] x86/alt: Drop explicit padding of origin sites
Date: Mon, 12 Feb 2018 11:23:06 +0000	[thread overview]
Message-ID: <1518434587-22827-7-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1518434587-22827-1-git-send-email-andrew.cooper3@citrix.com>

Now that the alternatives infrastructure can calculate the required padding
automatically, there is no need to hard code it.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
---
 xen/arch/x86/x86_64/compat/entry.S  |  2 +-
 xen/arch/x86/x86_64/entry.S         |  2 +-
 xen/include/asm-x86/nops.h          |  7 -------
 xen/include/asm-x86/spec_ctrl_asm.h | 19 ++++++++-----------
 4 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
index e93770f..db463c5 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -132,7 +132,7 @@ ENTRY(compat_restore_all_guest)
         jne   1b
 2:
 .endm
-	ALTERNATIVE_2 ".skip 45, 0x90", \
+	ALTERNATIVE_2 "", \
             alt_cr4_pv32, X86_FEATURE_XEN_SMEP, \
             alt_cr4_pv32, X86_FEATURE_XEN_SMAP
 
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index bd3819a..54a3b31 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -557,7 +557,7 @@ handle_exception_saved:
         testb $X86_EFLAGS_IF>>8,UREGS_eflags+1(%rsp)
         jz    exception_with_ints_disabled
 
-        ALTERNATIVE_2 "jmp .Lcr4_pv32_done; .skip 2, 0x90", \
+        ALTERNATIVE_2 "jmp .Lcr4_pv32_done", \
             __stringify(mov VCPU_domain(%rbx), %rax), X86_FEATURE_XEN_SMEP, \
             __stringify(mov VCPU_domain(%rbx), %rax), X86_FEATURE_XEN_SMAP
 
diff --git a/xen/include/asm-x86/nops.h b/xen/include/asm-x86/nops.h
index 61319cc..1a46b97 100644
--- a/xen/include/asm-x86/nops.h
+++ b/xen/include/asm-x86/nops.h
@@ -65,13 +65,6 @@
 #define ASM_NOP8 _ASM_MK_NOP(P6_NOP8)
 #define ASM_NOP9 _ASM_MK_NOP(P6_NOP9)
 
-#define ASM_NOP17 ASM_NOP8; ASM_NOP7; ASM_NOP2
-#define ASM_NOP21 ASM_NOP8; ASM_NOP8; ASM_NOP5
-#define ASM_NOP24 ASM_NOP8; ASM_NOP8; ASM_NOP8
-#define ASM_NOP29 ASM_NOP8; ASM_NOP8; ASM_NOP8; ASM_NOP5
-#define ASM_NOP32 ASM_NOP8; ASM_NOP8; ASM_NOP8; ASM_NOP8
-#define ASM_NOP40 ASM_NOP8; ASM_NOP8; ASM_NOP8; ASM_NOP8; ASM_NOP8
-
 #define ASM_NOP_MAX 9
 
 #endif /* __X86_ASM_NOPS_H__ */
diff --git a/xen/include/asm-x86/spec_ctrl_asm.h b/xen/include/asm-x86/spec_ctrl_asm.h
index 814f53d..c32c3e6 100644
--- a/xen/include/asm-x86/spec_ctrl_asm.h
+++ b/xen/include/asm-x86/spec_ctrl_asm.h
@@ -216,9 +216,8 @@
 
 /* Use after a VMEXIT from an HVM guest. */
 #define SPEC_CTRL_ENTRY_FROM_VMEXIT                                     \
-    ALTERNATIVE __stringify(ASM_NOP40),                                 \
-        DO_OVERWRITE_RSB, X86_FEATURE_RSB_VMEXIT;                       \
-    ALTERNATIVE_2 __stringify(ASM_NOP32),                               \
+    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_RSB_VMEXIT;           \
+    ALTERNATIVE_2 "",                                                   \
         __stringify(DO_SPEC_CTRL_ENTRY_FROM_VMEXIT                      \
                     ibrs_val=SPEC_CTRL_IBRS),                           \
         X86_FEATURE_XEN_IBRS_SET,                                       \
@@ -228,9 +227,8 @@
 
 /* Use after an entry from PV context (syscall/sysenter/int80/int82/etc). */
 #define SPEC_CTRL_ENTRY_FROM_PV                                         \
-    ALTERNATIVE __stringify(ASM_NOP40),                                 \
-        DO_OVERWRITE_RSB, X86_FEATURE_RSB_NATIVE;                       \
-    ALTERNATIVE_2 __stringify(ASM_NOP21),                               \
+    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_RSB_NATIVE;           \
+    ALTERNATIVE_2 "",                                                   \
         __stringify(DO_SPEC_CTRL_ENTRY maybexen=0                       \
                     ibrs_val=SPEC_CTRL_IBRS),                           \
         X86_FEATURE_XEN_IBRS_SET,                                       \
@@ -239,9 +237,8 @@
 
 /* Use in interrupt/exception context.  May interrupt Xen or PV context. */
 #define SPEC_CTRL_ENTRY_FROM_INTR                                       \
-    ALTERNATIVE __stringify(ASM_NOP40),                                 \
-        DO_OVERWRITE_RSB, X86_FEATURE_RSB_NATIVE;                       \
-    ALTERNATIVE_2 __stringify(ASM_NOP29),                               \
+    ALTERNATIVE "", DO_OVERWRITE_RSB, X86_FEATURE_RSB_NATIVE;           \
+    ALTERNATIVE_2 "",                                                   \
         __stringify(DO_SPEC_CTRL_ENTRY maybexen=1                       \
                     ibrs_val=SPEC_CTRL_IBRS),                           \
         X86_FEATURE_XEN_IBRS_SET,                                       \
@@ -250,13 +247,13 @@
 
 /* Use when exiting to Xen context. */
 #define SPEC_CTRL_EXIT_TO_XEN                                           \
-    ALTERNATIVE_2 __stringify(ASM_NOP17),                               \
+    ALTERNATIVE_2 "",                                                   \
         DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_XEN_IBRS_SET,             \
         DO_SPEC_CTRL_EXIT_TO_XEN, X86_FEATURE_XEN_IBRS_CLEAR
 
 /* Use when exiting to guest context. */
 #define SPEC_CTRL_EXIT_TO_GUEST                                         \
-    ALTERNATIVE_2 __stringify(ASM_NOP24),                               \
+    ALTERNATIVE_2 "",                                                   \
         DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_XEN_IBRS_SET,           \
         DO_SPEC_CTRL_EXIT_TO_GUEST, X86_FEATURE_XEN_IBRS_CLEAR
 
-- 
2.1.4


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  parent reply	other threads:[~2018-02-12 11:23 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-12 11:23 [PATCH 0/7] x86/alternatives: Support for automatic padding calculations Andrew Cooper
2018-02-12 11:23 ` [PATCH 1/7] x86/alt: Drop unused alternative infrastructure Andrew Cooper
2018-02-12 12:30   ` Wei Liu
2018-02-12 15:56   ` Roger Pau Monné
2018-02-12 15:58     ` Andrew Cooper
2018-02-13 14:22   ` Jan Beulich
2018-02-13 14:41     ` Andrew Cooper
2018-02-13 15:33       ` Jan Beulich
2018-02-14 10:02       ` Jan Beulich
2018-02-12 11:23 ` [PATCH 2/7] x86/alt: Clean up struct alt_instr and its users Andrew Cooper
2018-02-12 12:30   ` Wei Liu
2018-02-12 16:52   ` Roger Pau Monné
2018-02-12 17:18     ` Wei Liu
2018-02-12 17:53       ` Andrew Cooper
2018-02-13 14:26   ` Jan Beulich
2018-02-21 21:22   ` Konrad Rzeszutek Wilk
2018-02-12 11:23 ` [PATCH 3/7] x86/alt: Clean up the assembly used to generate alternatives Andrew Cooper
2018-02-12 12:30   ` Wei Liu
2018-02-12 17:26   ` Roger Pau Monné
2018-02-12 17:54     ` Andrew Cooper
2018-02-13 14:37   ` Jan Beulich
2018-02-23 14:03     ` Andrew Cooper
2018-02-23 15:12       ` Jan Beulich
2018-02-23 16:24         ` Andrew Cooper
2018-02-23 17:28           ` Jan Beulich
2018-02-12 11:23 ` [PATCH 4/7] x86/asm: Remove opencoded uses of altinstruction_entry Andrew Cooper
2018-02-12 12:30   ` Wei Liu
2018-02-12 12:34     ` Andrew Cooper
2018-02-13  9:56     ` Jan Beulich
2018-02-13 10:07       ` Andrew Cooper
2018-02-13 11:10         ` Jan Beulich
2018-02-12 12:52   ` Wei Liu
2018-02-12 17:46   ` Roger Pau Monné
2018-02-12 17:59     ` Andrew Cooper
2018-02-14  9:53   ` Jan Beulich
2018-02-12 11:23 ` [PATCH 5/7] x86/alt: Support for automatic padding calculations Andrew Cooper
2018-02-12 14:39   ` Wei Liu
2018-02-12 15:04     ` Andrew Cooper
2018-02-12 18:41       ` Roger Pau Monné
2018-02-12 18:45         ` Andrew Cooper
2018-02-12 18:09   ` Roger Pau Monné
2018-02-13  9:45   ` Roger Pau Monné
2018-02-13 10:09     ` Andrew Cooper
2018-02-13 10:26       ` Roger Pau Monné
2018-02-14  9:46   ` Jan Beulich
2018-02-12 11:23 ` Andrew Cooper [this message]
2018-02-12 14:39   ` [PATCH 6/7] x86/alt: Drop explicit padding of origin sites Wei Liu
2018-02-12 18:12   ` Roger Pau Monné
2018-02-14  9:53   ` Jan Beulich
2018-02-12 11:23 ` [PATCH 7/7] x86/build: Use new .nop directive when available Andrew Cooper
2018-02-12 14:40   ` Wei Liu
2018-02-13 11:08   ` Roger Pau Monné

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