KVM: arm64: Introduce hyp context

During __guest_enter, save and restore from a new hyp context rather
than the host context. This is preparation for separation of the hyp and
host context in nVHE.

Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200915104643.2543892-9-ascull@google.com

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 1e2491d..0b525e0 100644 (file)
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -12,6 +12,7 @@
 #include <asm/alternative.h>
 #include <asm/sysreg.h>
 
+DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
 DECLARE_PER_CPU(unsigned long, kvm_hyp_vector);
 
 #define read_sysreg_elx(r,nvh,vh)                                      \
@@ -89,7 +90,7 @@ void activate_traps_vhe_load(struct kvm_vcpu *vcpu);
 void deactivate_traps_vhe_put(void);
 #endif
 
-u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
+u64 __guest_enter(struct kvm_vcpu *vcpu);
 
 void __noreturn hyp_panic(void);
 #ifdef __KVM_NVHE_HYPERVISOR__

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 54bb0eb..9f419e4 100644 (file)
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -71,6 +71,7 @@ KVM_NVHE_ALIAS(kvm_update_va_mask);
 /* Global kernel state accessed by nVHE hyp code. */
 KVM_NVHE_ALIAS(arm64_ssbd_callback_required);
 KVM_NVHE_ALIAS(kvm_host_data);
+KVM_NVHE_ALIAS(kvm_hyp_ctxt);
 KVM_NVHE_ALIAS(kvm_hyp_vector);
 KVM_NVHE_ALIAS(kvm_vgic_global_state);
 

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index b6442c6..ae4b34f 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(struct kvm_cpu_context, kvm_hyp_ctxt);
 DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
 static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 
@@ -1542,6 +1543,7 @@ static int init_hyp_mode(void)
 
        for_each_possible_cpu(cpu) {
                struct kvm_host_data *cpu_data;
+               struct kvm_cpu_context *hyp_ctxt;
                unsigned long *vector;
 
                cpu_data = per_cpu_ptr(&kvm_host_data, cpu);
@@ -1552,6 +1554,14 @@ static int init_hyp_mode(void)
                        goto out_err;
                }
 
+               hyp_ctxt = per_cpu_ptr(&kvm_hyp_ctxt, cpu);
+               err = create_hyp_mappings(hyp_ctxt, hyp_ctxt + 1, PAGE_HYP);
+
+               if (err) {
+                       kvm_err("Cannot map hyp context: %d\n", err);
+                       goto out_err;
+               }
+
                vector = per_cpu_ptr(&kvm_hyp_vector, cpu);
                err = create_hyp_mappings(vector, vector + 1, PAGE_HYP);
 

diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 76e7eaf..9551d7f 100644 (file)
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -57,15 +57,15 @@
 .endm
 
 /*
- * u64 __guest_enter(struct kvm_vcpu *vcpu,
- *                  struct kvm_cpu_context *host_ctxt);
+ * u64 __guest_enter(struct kvm_vcpu *vcpu);
  */
 SYM_FUNC_START(__guest_enter)
        // x0: vcpu
-       // x1: host context
-       // x2-x17: clobbered by macros
+       // x1-x17: clobbered by macros
        // x29: guest context
 
+       hyp_adr_this_cpu x1, kvm_hyp_ctxt, x2
+
        // Store the host regs
        save_callee_saved_regs x1
 
@@ -148,7 +148,7 @@ SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
        // Store the guest's sp_el0
        save_sp_el0     x1, x2
 
-       get_host_ctxt   x2, x3
+       hyp_adr_this_cpu x2, kvm_hyp_ctxt, x3
 
        // Macro ptrauth_switch_to_guest format:
        //      ptrauth_switch_to_host(guest cxt, host cxt, tmp1, tmp2, tmp3)

diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 96ea3fd..afe7140 100644 (file)
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -381,7 +381,7 @@ static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
            !esr_is_ptrauth_trap(kvm_vcpu_get_esr(vcpu)))
                return false;
 
-       ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+       ctxt = __hyp_this_cpu_ptr(kvm_hyp_ctxt);
        __ptrauth_save_key(ctxt, APIA);
        __ptrauth_save_key(ctxt, APIB);
        __ptrauth_save_key(ctxt, APDA);

diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 0753840..c99945c 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -209,7 +209,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 
        do {
                /* Jump in the fire! */
-               exit_code = __guest_enter(vcpu, host_ctxt);
+               exit_code = __guest_enter(vcpu);
 
                /* And we're baaack! */
        } while (fixup_guest_exit(vcpu, &exit_code));

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index b49cf53..cf477f8 100644 (file)
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -135,7 +135,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
 
        do {
                /* Jump in the fire! */
-               exit_code = __guest_enter(vcpu, host_ctxt);
+               exit_code = __guest_enter(vcpu);
 
                /* And we're baaack! */
        } while (fixup_guest_exit(vcpu, &exit_code));