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ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling

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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: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Russell King 2018-05-15 17:04:10 +01:00
parent 3c908e1639
commit b800acfc70
1 changed files with 16 additions and 1 deletions
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17
arch/arm/kvm/hyp/hyp-entry.S
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@ -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