[xen master] x86/entry: replace two GET_CURRENT() uses

[patchbot@xxxxxxx]

commit e047b8d0fa05c6c051ad6e4f5ff6e0fe426965b3
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jan 25 16:10:58 2024 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jan 25 16:10:58 2024 +0100

    x86/entry: replace two GET_CURRENT() uses
    
    Now that we have %r14 set up using GET_STACK_END() in a number of
    places, in two places we can eliminate the redundancy of GET_CURRENT()
    also invoking that macro. In handle_ist_exception() actually go a step
    farther and avoid using %rbx altogether when retrieving the processor
    ID: Obtain the current vCPU pointer only in the PV32-specific code
    actually needing it.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/x86_64/asm-offsets.c | 1 +
 xen/arch/x86/x86_64/entry.S       | 6 +++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/x86_64/asm-offsets.c 
b/xen/arch/x86/x86_64/asm-offsets.c
index 57b73a4e62..f9546ec60b 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -118,6 +118,7 @@ void __dummy__(void)
 #endif
 
     OFFSET(CPUINFO_guest_cpu_user_regs, struct cpu_info, guest_cpu_user_regs);
+    OFFSET(CPUINFO_processor_id, struct cpu_info, processor_id);
     OFFSET(CPUINFO_verw_sel, struct cpu_info, verw_sel);
     OFFSET(CPUINFO_current_vcpu, struct cpu_info, current_vcpu);
     OFFSET(CPUINFO_per_cpu_offset, struct cpu_info, per_cpu_offset);
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index c3f6b667a7..5dab3e4832 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -749,7 +749,7 @@ FUNC(handle_exception, 0)
 .Lxcpt_cr3_okay:
 
 handle_exception_saved:
-        GET_CURRENT(bx)
+        mov   STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
         testb $X86_EFLAGS_IF>>8,UREGS_eflags+1(%rsp)
         jz    exception_with_ints_disabled
 
@@ -1130,9 +1130,8 @@ FUNC(handle_ist_exception)
 #ifdef CONFIG_PV
         testb $3,UREGS_cs(%rsp)
         jz    restore_all_xen
-        GET_CURRENT(bx)
         /* Send an IPI to ourselves to cover for the lack of event checking. */
-        movl  VCPU_processor(%rbx),%eax
+        mov   STACK_CPUINFO_FIELD(processor_id)(%r14), %eax
         shll  $IRQSTAT_shift,%eax
         leaq  irq_stat+IRQSTAT_softirq_pending(%rip),%rcx
         cmpl  $0,(%rcx,%rax,1)
@@ -1141,6 +1140,7 @@ FUNC(handle_ist_exception)
         call  send_IPI_self
 1:
 #ifdef CONFIG_PV32
+        mov   STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
         movq  VCPU_domain(%rbx),%rax
         cmpb  $0,DOMAIN_is_32bit_pv(%rax)
         je    restore_all_guest
--
generated by git-patchbot for /home/xen/git/xen.git#master