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Commit b800acfc authored by Russell King's avatar Russell King
Browse files

ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling 



We want SMCCC_ARCH_WORKAROUND_1 to be fast. As fast as possible.
So let's intercept it as early as we can by testing for the
function call number as soon as we've identified a HVC call
coming from the guest.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: default avatarTony Lindgren <tony@atomide.com>
Reviewed-by: default avatarTony Lindgren <tony@atomide.com>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 3c908e16

arch/arm/kvm/hyp/hyp-entry.S

+16 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */



#include <linux/arm-smccc.h>

#include <linux/linkage.h>

#include <asm/kvm_arm.h>

#include <asm/kvm_asm.h>
@@ -202,7 +203,7 @@ hyp_hvc: 
	lsr     r2, r2, #16

	and     r2, r2, #0xff

	cmp     r2, #0

	bne	guest_trap		@ Guest called HVC

	bne	guest_hvc_trap		@ Guest called HVC



	/*

	 * Getting here means host called HVC, we shift parameters and branch
@@ -253,6 +254,20 @@ THUMB( orr lr, #1) 
	pop	{r2, lr}

	eret



guest_hvc_trap:

	movw	r2, #:lower16:ARM_SMCCC_ARCH_WORKAROUND_1

	movt	r2, #:upper16:ARM_SMCCC_ARCH_WORKAROUND_1

	ldr	r0, [sp]		@ Guest's r0

	teq	r0, r2

	bne	guest_trap

	add	sp, sp, #12

	@ Returns:

	@ r0 = 0

	@ r1 = HSR value (perfectly predictable)

	@ r2 = ARM_SMCCC_ARCH_WORKAROUND_1

	mov	r0, #0

	eret



guest_trap:

	load_vcpu r0			@ Load VCPU pointer to r0