|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 5/7] x86: make entry point code build when !CONFIG_PV
On Mon, Nov 05, 2018 at 02:33:23PM +0000, Andrew Cooper wrote:
> On 02/11/18 15:55, Wei Liu wrote:
> > Skip building x86_64/compat/entry.S and put CONFIG_PV in
> > x86_64/entry.S.
> >
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> > ---
> > v3:
> > 1. make CR4_PV32_RESTORE expand to nothing when !PV
> > 2. use unconditional jmp and add assertions
> >
> > v2: new
> > ---
> > xen/arch/x86/x86_64/Makefile | 2 +-
> > xen/arch/x86/x86_64/entry.S | 39 +++++++++++++++++++++++++++++++++-
> > xen/include/asm-x86/asm_defns.h | 4 +++-
> > 3 files changed, 43 insertions(+), 2 deletions(-)
> >
> > diff --git a/xen/arch/x86/x86_64/Makefile b/xen/arch/x86/x86_64/Makefile
> > index f336a6a..4bfa148 100644
> > --- a/xen/arch/x86/x86_64/Makefile
> > +++ b/xen/arch/x86/x86_64/Makefile
> > @@ -1,4 +1,4 @@
> > -subdir-y += compat
> > +subdir-$(CONFIG_PV) += compat
> >
> > obj-bin-y += entry.o
> > obj-y += traps.o
> > diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
> > index 9b02899..975ed6a 100644
> > --- a/xen/arch/x86/x86_64/entry.S
> > +++ b/xen/arch/x86/x86_64/entry.S
> > @@ -15,6 +15,18 @@
> > #include <public/xen.h>
> > #include <irq_vectors.h>
> >
> > +#ifndef NDEBUG
> > +/* %rsp: struct cpu_user_regs */
> > +#define ASSERT_INTERRUPTED_XEN_CONTEXT \
>
> Could I suggest ASSERT_CONTEXT_IS_XEN which I think fits better in some
> of the cases below?
>
> > + testb $3, UREGS_cs(%rsp); \
> > + jz 1f; \
> > + ASSERT_FAILED("INTERRUPTED XEN CONTEXT"); \
>
> This probably wants to be:
>
> .macro ASSERT_CONTEXT_IS_XEN
> #ifndef NDEBUG
> testb $3, UREGS_cs(%rsp);
> UNLIKELY_START(nz, ASSERT_XEN_\@);
> ASSERT_FAILED("CONTEXT IS XEN");
> __UNLIKELY_END(ASSERT_XEN_\@);
> #endif
> .endm
This works. I have deleted all semicolons though.
(To avoid posting other patches)
---8<---
From 8f3ce0b0a5b6a215d4309d77d2c63229fb4af900 Mon Sep 17 00:00:00 2001
From: Wei Liu <wei.liu2@xxxxxxxxxx>
Date: Fri, 19 Oct 2018 12:32:12 +0100
Subject: [PATCH] x86: make entry point code build when !CONFIG_PV
Skip building x86_64/compat/entry.S and put CONFIG_PV in
x86_64/entry.S.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
v4:
1. Change name to ASSERT_CONTEXT_IS_XEN
2. Use UNLIKELY
v3:
1. make CR4_PV32_RESTORE expand to nothing when !PV
2. use unconditional jmp and add assertions
v2: new
---
xen/arch/x86/x86_64/Makefile | 2 +-
xen/arch/x86/x86_64/entry.S | 38 +++++++++++++++++++++++++++++++++++++-
xen/include/asm-x86/asm_defns.h | 4 ++++
3 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/x86_64/Makefile b/xen/arch/x86/x86_64/Makefile
index f336a6ae65..4bfa1480eb 100644
--- a/xen/arch/x86/x86_64/Makefile
+++ b/xen/arch/x86/x86_64/Makefile
@@ -1,4 +1,4 @@
-subdir-y += compat
+subdir-$(CONFIG_PV) += compat
obj-bin-y += entry.o
obj-y += traps.o
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 8e12decea8..e8eae3b08d 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -15,6 +15,17 @@
#include <public/xen.h>
#include <irq_vectors.h>
+/* %rsp: struct cpu_user_regs */
+.macro ASSERT_CONTEXT_IS_XEN
+#ifndef NDEBUG
+ testb $3, UREGS_cs(%rsp)
+ UNLIKELY_START(nz, ASSERT_XEN_\@)
+ ASSERT_FAILED("INTERRUPTED XEN CONTEXT")
+ __UNLIKELY_END(ASSERT_XEN_\@)
+#endif
+.endm
+
+#ifdef CONFIG_PV
/* %rbx: struct vcpu */
ENTRY(switch_to_kernel)
leaq VCPU_trap_bounce(%rbx),%rdx
@@ -522,6 +533,7 @@ ENTRY(dom_crash_sync_extable)
xorl %edi,%edi
jmp asm_domain_crash_synchronous /* Does not return */
.popsection
+#endif /* CONFIG_PV */
/* --- CODE BELOW THIS LINE (MOSTLY) NOT GUEST RELATED --- */
@@ -529,6 +541,7 @@ ENTRY(dom_crash_sync_extable)
/* No special register assumptions. */
ENTRY(ret_from_intr)
+#ifdef CONFIG_PV
GET_CURRENT(bx)
testb $3, UREGS_cs(%rsp)
jz restore_all_xen
@@ -536,6 +549,10 @@ ENTRY(ret_from_intr)
cmpb $0, DOMAIN_is_32bit_pv(%rax)
je test_all_events
jmp compat_test_all_events
+#else
+ ASSERT_CONTEXT_IS_XEN
+ jmp restore_all_xen
+#endif
.section .text.entry, "ax", @progbits
@@ -618,6 +635,7 @@ handle_exception_saved:
testb $X86_EFLAGS_IF>>8,UREGS_eflags+1(%rsp)
jz exception_with_ints_disabled
+#ifdef CONFIG_PV
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
@@ -657,6 +675,9 @@ handle_exception_saved:
test $~(PFEC_write_access|PFEC_insn_fetch),%eax
jz compat_test_all_events
.Lcr4_pv32_done:
+#else
+ ASSERT_CONTEXT_IS_XEN
+#endif /* CONFIG_PV */
sti
1: movq %rsp,%rdi
movzbl UREGS_entry_vector(%rsp),%eax
@@ -666,12 +687,17 @@ handle_exception_saved:
INDIRECT_CALL %rdx
mov %r15, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
mov %r13b, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
+#ifdef CONFIG_PV
testb $3,UREGS_cs(%rsp)
jz restore_all_xen
movq VCPU_domain(%rbx),%rax
cmpb $0, DOMAIN_is_32bit_pv(%rax)
jne compat_test_all_events
jmp test_all_events
+#else
+ ASSERT_CONTEXT_IS_XEN
+ jmp restore_all_xen
+#endif
/* No special register assumptions. */
exception_with_ints_disabled:
@@ -822,6 +848,7 @@ handle_ist_exception:
mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
.List_cr3_okay:
+#ifdef CONFIG_PV
CR4_PV32_RESTORE
testb $3,UREGS_cs(%rsp)
jz 1f
@@ -836,7 +863,11 @@ handle_ist_exception:
movl $UREGS_kernel_sizeof/8,%ecx
movq %rdi,%rsp
rep movsq
-1: movq %rsp,%rdi
+1:
+#else
+ ASSERT_CONTEXT_IS_XEN
+#endif
+ movq %rsp,%rdi
movzbl UREGS_entry_vector(%rsp),%eax
leaq exception_table(%rip),%rdx
mov (%rdx, %rax, 8), %rdx
@@ -847,6 +878,7 @@ handle_ist_exception:
jne ret_from_intr
/* We want to get straight to the IRET on the NMI exit path. */
+#ifdef CONFIG_PV
testb $3,UREGS_cs(%rsp)
jz restore_all_xen
GET_CURRENT(bx)
@@ -862,6 +894,10 @@ handle_ist_exception:
cmpb $0,DOMAIN_is_32bit_pv(%rax)
je restore_all_guest
jmp compat_restore_all_guest
+#else
+ ASSERT_CONTEXT_IS_XEN
+ jmp restore_all_xen
+#endif
ENTRY(machine_check)
pushq $0
diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h
index da504eaec2..e688cf1c16 100644
--- a/xen/include/asm-x86/asm_defns.h
+++ b/xen/include/asm-x86/asm_defns.h
@@ -321,10 +321,14 @@ static always_inline void stac(void)
subq $-(UREGS_error_code-UREGS_r15+\adj), %rsp
.endm
+#ifdef CONFIG_PV
#define CR4_PV32_RESTORE \
ALTERNATIVE_2 "", \
"call cr4_pv32_restore", X86_FEATURE_XEN_SMEP, \
"call cr4_pv32_restore", X86_FEATURE_XEN_SMAP
+#else
+#define CR4_PV32_RESTORE
+#endif
#include <asm/spec_ctrl_asm.h>
--
2.11.0
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |