Commit 04ac88ab authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/fpu, kvm: Remove host CR0.TS manipulation 



Now that x86 always uses eager FPU switching on the host, there's no
need for KVM to manipulate the host's CR0.TS.

This should be both simpler and faster.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm list <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/b212064922537c05d0c81d931fc4dbe769127ce7.1477951965.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5a83d60c

arch/x86/kvm/vmx.c

+4 −8
Original line number Diff line number Diff line
@@ -2144,12 +2144,6 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx) 
#endif

	if (vmx->host_state.msr_host_bndcfgs)

		wrmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_bndcfgs);

	/*

	 * If the FPU is not active (through the host task or

	 * the guest vcpu), then restore the cr0.TS bit.

	 */

	if (!fpregs_active() && !vmx->vcpu.guest_fpu_loaded)

		stts();

	load_gdt(this_cpu_ptr(&host_gdt));

}
@@ -4871,9 +4865,11 @@ static void vmx_set_constant_host_state(struct vcpu_vmx *vmx) 
	u32 low32, high32;

	unsigned long tmpl;

	struct desc_ptr dt;

	unsigned long cr4;

	unsigned long cr0, cr4;



	vmcs_writel(HOST_CR0, read_cr0() & ~X86_CR0_TS);  /* 22.2.3 */

	cr0 = read_cr0();

	WARN_ON(cr0 & X86_CR0_TS);

	vmcs_writel(HOST_CR0, cr0);  /* 22.2.3 */

	vmcs_writel(HOST_CR3, read_cr3());  /* 22.2.3  FIXME: shadow tables */



	/* Save the most likely value for this task's CR4 in the VMCS. */

arch/x86/kvm/x86.c

+0 −5
Original line number Diff line number Diff line
@@ -5060,11 +5060,6 @@ static void emulator_get_fpu(struct x86_emulate_ctxt *ctxt) 
{

	preempt_disable();

	kvm_load_guest_fpu(emul_to_vcpu(ctxt));

	/*

	 * CR0.TS may reference the host fpu state, not the guest fpu state,

	 * so it may be clear at this point.

	 */

	clts();

}



static void emulator_put_fpu(struct x86_emulate_ctxt *ctxt)