KVM: arm64: Save chosen hyp vector to a percpu variable

Introduce a percpu variable to hold the address of the selected hyp
vector that will be used with guests. This avoids the selection process
each time a guest is being entered and can be used by nVHE when a
separate vector is introduced for the host.

Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-6-ascull@google.com

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 3de99b3..1e2491d 100644 (file)
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -12,6 +12,8 @@
 #include <asm/alternative.h>
 #include <asm/sysreg.h>
 
+DECLARE_PER_CPU(unsigned long, kvm_hyp_vector);
+
 #define read_sysreg_elx(r,nvh,vh)                                      \
        ({                                                              \
                u64 reg;                                                \

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 1af4c77..77fc856 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -47,6 +47,7 @@ __asm__(".arch_extension      virt");
 #endif
 
 DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
+DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 
 /* The VMID used in the VTTBR */
@@ -1276,7 +1277,7 @@ static void cpu_init_hyp_mode(void)
 
        pgd_ptr = kvm_mmu_get_httbr();
        hyp_stack_ptr = __this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE;
-       vector_ptr = (unsigned long)kvm_get_hyp_vector();
+       vector_ptr = __this_cpu_read(kvm_hyp_vector);
 
        /*
         * Call initialization code, and switch to the full blown HYP code.
@@ -1309,6 +1310,8 @@ static void cpu_hyp_reinit(void)
 
        cpu_hyp_reset();
 
+       __this_cpu_write(kvm_hyp_vector, (unsigned long)kvm_get_hyp_vector());
+
        if (is_kernel_in_hyp_mode())
                kvm_timer_init_vhe();
        else

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index c1fd475..b49cf53 100644 (file)
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -59,7 +59,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
 
        write_sysreg(val, cpacr_el1);
 
-       write_sysreg(kvm_get_hyp_vector(), vbar_el1);
+       write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el1);
 }
 NOKPROBE_SYMBOL(__activate_traps);