[xen master] x86/svm: Remove regs param from asm-called functions

[patchbot@xxxxxxx]

commit c76e4ff7d531ee2bf37c9d4037c8645f9e586fcd
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Aug 10 21:25:52 2022 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Feb 21 15:00:32 2023 +0000

    x86/svm: Remove regs param from asm-called functions
    
    It is easier just to make the functions void and let the compiler do the 
(not
    very) hard work.
    
    Passing regs is a bit weird for HVM guests anyway, because the resulting
    pointer is invariant (this isn't native exception handling where the regs
    pointers *are* important), and all functions calculate current themselves
    which is another invariant.
    
    Finally, the compiler can merge the get_cpu_info() calculation which is 
common
    to both current and guest_cpu_user_regs(), meaning the delta in C really is
    just one LEA, and not any more expensive than MOV's in ASM anyway.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/svm/entry.S     | 3 ---
 xen/arch/x86/hvm/svm/nestedsvm.c | 3 ++-
 xen/arch/x86/hvm/svm/svm.c       | 6 ++++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/entry.S b/xen/arch/x86/hvm/svm/entry.S
index 981cd82e7c..ad582f54b3 100644
--- a/xen/arch/x86/hvm/svm/entry.S
+++ b/xen/arch/x86/hvm/svm/entry.S
@@ -28,7 +28,6 @@ ENTRY(svm_asm_do_resume)
         GET_CURRENT(bx)
 .Lsvm_do_resume:
         call svm_intr_assist
-        mov  %rsp,%rdi
         call nsvm_vcpu_switch
         ASSERT_NOT_IN_ATOMIC
 
@@ -54,7 +53,6 @@ UNLIKELY_START(ne, nsvm_hap)
         jmp  .Lsvm_do_resume
 __UNLIKELY_END(nsvm_hap)
 
-        mov  %rsp, %rdi
         call svm_vmenter_helper
 
         clgi
@@ -134,7 +132,6 @@ __UNLIKELY_END(nsvm_hap)
          */
         stgi
 GLOBAL(svm_stgi_label)
-        mov  %rsp,%rdi
         call svm_vmexit_handler
         jmp  .Lsvm_do_resume
 
diff --git a/xen/arch/x86/hvm/svm/nestedsvm.c b/xen/arch/x86/hvm/svm/nestedsvm.c
index 9f5f35f16a..77f7547360 100644
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -1460,8 +1460,9 @@ nestedsvm_vcpu_vmexit(struct vcpu *v, struct 
cpu_user_regs *regs,
 }
 
 /* VCPU switch */
-void nsvm_vcpu_switch(struct cpu_user_regs *regs)
+void nsvm_vcpu_switch(void)
 {
+    struct cpu_user_regs *regs = guest_cpu_user_regs();
     struct vcpu *v = current;
     struct nestedvcpu *nv;
     struct nestedsvm *svm;
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index f412b537aa..9c43227b76 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1055,8 +1055,9 @@ static void noreturn cf_check svm_do_resume(void)
     reset_stack_and_jump(svm_asm_do_resume);
 }
 
-void svm_vmenter_helper(const struct cpu_user_regs *regs)
+void svm_vmenter_helper(void)
 {
+    const struct cpu_user_regs *regs = guest_cpu_user_regs();
     struct vcpu *curr = current;
     struct vmcb_struct *vmcb = curr->arch.hvm.svm.vmcb;
 
@@ -2585,8 +2586,9 @@ const struct hvm_function_table * __init start_svm(void)
     return &svm_function_table;
 }
 
-void svm_vmexit_handler(struct cpu_user_regs *regs)
+void svm_vmexit_handler(void)
 {
+    struct cpu_user_regs *regs = guest_cpu_user_regs();
     uint64_t exit_reason;
     struct vcpu *v = current;
     struct vmcb_struct *vmcb = v->arch.hvm.svm.vmcb;
--
generated by git-patchbot for /home/xen/git/xen.git#master