[PATCH v3 14/15] ARM: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
From: Russell King <hidden>
Date: 2018-05-25 14:01:34
Also in:
kvmarm
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
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 <redacted> --- arch/arm/kvm/hyp/hyp-entry.S | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S
index 918a05dd2d63..aa3f9a9837ac 100644
--- a/arch/arm/kvm/hyp/hyp-entry.S
+++ b/arch/arm/kvm/hyp/hyp-entry.S@@ -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 @@ ENDPROC(__hyp_do_panic) 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
--
2.7.4