4.9-stable review patch. If anyone has any objections, please let me know.
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From: Russell King rmk+kernel@armlinux.org.uk
Commit b800acfc70d9fb81fbd6df70f2cf5e20f70023d0 upstream.
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 Signed-off-by: David A. Long dave.long@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/kvm/hyp/hyp-entry.S | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- 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 @@ 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 @@ -235,6 +236,20 @@ THUMB( orr lr, #1) pop {r2, lr} 1: 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