File 25200-x86_64-trap-bounce-flags.patch of Package xen
References: bnc#757970
# HG changeset patch
# User Jan Beulich <jbeulich@suse.com>
# Date 1334669633 -7200
# Node ID 80f4113be5007f5b8a61048272193ce134b4fc28
# Parent 6092641e364428e7be20c9e23497d7a1fc535112
x86-64: fix #GP generation in assembly code
When guest use of sysenter (64-bit PV guest) or syscall (32-bit PV
guest) gets converted into a GP fault (due to no callback having got
registered), we must
- honor the GP fault handler's request the keep enabled or mask event
delivery
- not allow TBF_EXCEPTION to remain set past the generation of the
(guest) exception in the vCPU's trap_bounce.flags, as that would
otherwise allow for the next exception occurring in guest mode,
should it happen to get handled in Xen itself, to nevertheless get
bounced to the guest kernel.
Also, just like compat mode syscall handling already did, native mode
sysenter handling should, when converting to #GP, subtract 2 from the
RIP present in the frame so that the guest's GP fault handler would
see the fault pointing to the offending instruction instead of past it.
Finally, since those exception generating code blocks needed to be
modified anyway, convert them to make use of UNLIKELY_{START,END}().
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
# HG changeset patch
# User Jan Beulich <jbeulich@suse.com>
# Date 1334675825 -7200
# Node ID 569d6f05e1ef3146c269bca6313e2777420d616d
# Parent cf129a80e47e3664eb14070600a3b5c8c2a60440
x86-64: fix updating of UREGS_rip when converting sysenter to #GP
(I spotted this copy-and-paste mistake only when backporting c/s
25200:80f4113be500 to 4.1 and 4.0.)
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -90,6 +90,8 @@ void __dummy__(void)
arch.guest_context.trap_ctxt[TRAP_gp_fault].address);
OFFSET(VCPU_gp_fault_sel, struct vcpu,
arch.guest_context.trap_ctxt[TRAP_gp_fault].cs);
+ OFFSET(VCPU_gp_fault_flags, struct vcpu,
+ arch.guest_context.trap_ctxt[TRAP_gp_fault].flags);
OFFSET(VCPU_kernel_sp, struct vcpu, arch.guest_context.kernel_sp);
OFFSET(VCPU_kernel_ss, struct vcpu, arch.guest_context.kernel_ss);
OFFSET(VCPU_guest_context_flags, struct vcpu, arch.guest_context.flags);
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -214,6 +214,7 @@ compat_failsafe_callback:
ENTRY(compat_post_handle_exception)
testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx)
jz compat_test_all_events
+.Lcompat_bounce_exception:
call compat_create_bounce_frame
movb $0,TRAPBOUNCE_flags(%rdx)
jmp compat_test_all_events
@@ -226,19 +227,20 @@ ENTRY(compat_syscall)
leaq VCPU_trap_bounce(%rbx),%rdx
testl $~3,%esi
leal (,%rcx,TBF_INTERRUPT),%ecx
- jz 2f
-1: movq %rax,TRAPBOUNCE_eip(%rdx)
- movw %si,TRAPBOUNCE_cs(%rdx)
- movb %cl,TRAPBOUNCE_flags(%rdx)
- call compat_create_bounce_frame
- jmp compat_test_all_events
-2: movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
+UNLIKELY_START(z, compat_syscall_gpf)
+ movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
subl $2,UREGS_rip(%rsp)
- movq VCPU_gp_fault_addr(%rbx),%rax
- movzwl VCPU_gp_fault_sel(%rbx),%esi
- movb $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl
movl $0,TRAPBOUNCE_error_code(%rdx)
- jmp 1b
+ movl VCPU_gp_fault_addr(%rbx),%eax
+ movzwl VCPU_gp_fault_sel(%rbx),%esi
+ testb $4,VCPU_gp_fault_flags(%rbx)
+ setnz %cl
+ leal TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx
+UNLIKELY_END(compat_syscall_gpf)
+ movq %rax,TRAPBOUNCE_eip(%rdx)
+ movw %si,TRAPBOUNCE_cs(%rdx)
+ movb %cl,TRAPBOUNCE_flags(%rdx)
+ jmp .Lcompat_bounce_exception
ENTRY(compat_sysenter)
cmpl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -278,19 +278,21 @@ sysenter_eflags_saved:
leaq VCPU_trap_bounce(%rbx),%rdx
testq %rax,%rax
leal (,%rcx,TBF_INTERRUPT),%ecx
- jz 2f
-1: movq VCPU_domain(%rbx),%rdi
+UNLIKELY_START(z, sysenter_gpf)
+ movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
+ subq $2,UREGS_rip(%rsp)
+ movl %eax,TRAPBOUNCE_error_code(%rdx)
+ movq VCPU_gp_fault_addr(%rbx),%rax
+ testb $4,VCPU_gp_fault_flags(%rbx)
+ setnz %cl
+ leal TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx
+UNLIKELY_END(sysenter_gpf)
+ movq VCPU_domain(%rbx),%rdi
movq %rax,TRAPBOUNCE_eip(%rdx)
movb %cl,TRAPBOUNCE_flags(%rdx)
testb $1,DOMAIN_is_32bit_pv(%rdi)
jnz compat_sysenter
- call create_bounce_frame
- jmp test_all_events
-2: movl %eax,TRAPBOUNCE_error_code(%rdx)
- movq VCPU_gp_fault_addr(%rbx),%rax
- movb $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl
- movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
- jmp 1b
+ jmp .Lbounce_exception
ENTRY(int80_direct_trap)
pushq $0
@@ -482,6 +484,7 @@ handle_exception_saved:
jnz compat_post_handle_exception
testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx)
jz test_all_events
+.Lbounce_exception:
call create_bounce_frame
movb $0,TRAPBOUNCE_flags(%rdx)
jmp test_all_events
