Commit:     ff593e5abebd899b0b41c11280e2fbeff4103375
Parent:     c20363006af64cf397519da5e984b18e6bdffd82
Author:     Laurent Vivier <[EMAIL PROTECTED]>
AuthorDate: Thu Oct 25 14:18:55 2007 +0200
Committer:  Avi Kivity <[EMAIL PROTECTED]>
CommitDate: Wed Jan 30 17:52:56 2008 +0200

    KVM: VMX: Let gcc to choose which registers to save (i386)
    This patch lets GCC to determine which registers to save when we
    switch to/from a VCPU in the case of intel i386.
    * Original code saves following registers:
        eax, ebx, ecx, edx, edi, esi, ebp (using popa)
    * Patched code:
      - informs GCC that we modify following registers
        using the clobber description:
        ebx, edi, rsi
      - doesn't save eax because it is an output operand (vmx->fail)
      - cannot put ecx in clobber description because it is an input operand,
        but as we modify it and we want to keep its value (vcpu), we must
        save it (pop/push)
      - ebp is saved (pop/push) because GCC seems to ignore its use the clobber
      - edx is saved (pop/push) because it is reserved by GCC (REGPARM) and
        cannot be put in the clobber description.
      - line "mov (%%esp), %3 \n\t" has been removed because %3
        is ecx and ecx is restored just after.
    Signed-off-by: Laurent Vivier <[EMAIL PROTECTED]>
    Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
 drivers/kvm/vmx.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 56c9bcc..2d7d638 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2268,7 +2268,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct 
kvm_run *kvm_run)
                "push %%rdx; push %%rbp;"
                "push %%rcx \n\t"
-               "pusha; push %%ecx \n\t"
+               "push %%edx; push %%ebp;"
+               "push %%ecx \n\t"
                ASM_VMX_VMWRITE_RSP_RDX "\n\t"
                /* Check if vmlaunch of vmresume is needed */
@@ -2342,9 +2343,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct 
kvm_run *kvm_run)
                "mov %%ebp, %c[rbp](%3) \n\t"
                "mov %%cr2, %%eax  \n\t"
                "mov %%eax, %c[cr2](%3) \n\t"
-               "mov (%%esp), %3 \n\t"
-               "pop %%ecx; popa \n\t"
+               "pop %%ecx; pop %%ebp; pop %%edx \n\t"
                "setbe %0 \n\t"
              : "=q" (vmx->fail)
@@ -2372,6 +2372,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct 
kvm_run *kvm_run)
 #ifdef CONFIG_X86_64
                , "rbx", "rdi", "rsi"
                , "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
+               , "ebx", "edi", "rsi"
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