From 464d1a78fbf8cf6c7fd970e7b3e2db50a320ce28 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 13 Feb 2007 13:26:20 +0100 Subject: [PATCH] i386: Convert i386 PDA code to use %fs Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Ian Campbell Acked-by: Ingo Molnar Acked-by: Zachary Amsden Cc: Eric Dumazet Signed-off-by: Frederik Deweerdt Signed-off-by: Andrew Morton --- drivers/kvm/vmx.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/kvm/vmx.c') diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 1e640b89917..fd4e9173438 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1879,12 +1879,6 @@ again: asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS)); - /* - * Profile KVM exit RIPs: - */ - if (unlikely(prof_on == KVM_PROFILING)) - profile_hit(KVM_PROFILING, (void *)vmcs_readl(GUEST_RIP)); - kvm_run->exit_type = 0; if (fail) { kvm_run->exit_type = KVM_EXIT_TYPE_FAIL_ENTRY; @@ -1907,6 +1901,12 @@ again: reload_tss(); } + /* + * Profile KVM exit RIPs: + */ + if (unlikely(prof_on == KVM_PROFILING)) + profile_hit(KVM_PROFILING, (void *)vmcs_readl(GUEST_RIP)); + vcpu->launched = 1; kvm_run->exit_type = KVM_EXIT_TYPE_VM_EXIT; r = kvm_handle_exit(kvm_run, vcpu); -- cgit v1.2.3