KVM: arm64: Intercept host's SYSTEM_SUSPEND PSCI SMCs

Add a handler of SYSTEM_SUSPEND host PSCI SMCs. The semantics are
equivalent to CPU_SUSPEND, typically called on the last online CPU.
Reuse the same entry point and boot args struct as CPU_SUSPEND.

Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-24-dbrazdil@google.com

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 0853f62..a2e2515 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -151,7 +151,7 @@ SYM_CODE_START(kvm_hyp_cpu_entry)
 SYM_CODE_END(kvm_hyp_cpu_entry)
 
 /*
- * PSCI CPU_SUSPEND entry point
+ * PSCI CPU_SUSPEND / SYSTEM_SUSPEND entry point
  *
  * x0: struct kvm_nvhe_init_params PA
  */

diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
index 688cf7f..08dc9de 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c
+++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
@@ -201,6 +201,30 @@ static int psci_cpu_suspend(u64 func_id, struct kvm_cpu_context *host_ctxt)
                         __hyp_pa(init_params));
 }
 
+static int psci_system_suspend(u64 func_id, struct kvm_cpu_context *host_ctxt)
+{
+       DECLARE_REG(unsigned long, pc, host_ctxt, 1);
+       DECLARE_REG(unsigned long, r0, host_ctxt, 2);
+
+       struct psci_boot_args *boot_args;
+       struct kvm_nvhe_init_params *init_params;
+
+       boot_args = this_cpu_ptr(hyp_symbol_addr(suspend_args));
+       init_params = this_cpu_ptr(hyp_symbol_addr(kvm_init_params));
+
+       /*
+        * No need to acquire a lock before writing to boot_args because a core
+        * can only suspend itself. Racy CPU_ON calls use a separate struct.
+        */
+       boot_args->pc = pc;
+       boot_args->r0 = r0;
+
+       /* Will only return on error. */
+       return psci_call(func_id,
+                        __hyp_pa(hyp_symbol_addr(kvm_hyp_cpu_resume)),
+                        __hyp_pa(init_params), 0);
+}
+
 asmlinkage void __noreturn kvm_host_psci_cpu_entry(bool is_cpu_on)
 {
        struct psci_boot_args *boot_args;
@@ -265,6 +289,8 @@ static unsigned long psci_1_0_handler(u64 func_id, struct kvm_cpu_context *host_
        case PSCI_1_0_FN_SET_SUSPEND_MODE:
        case PSCI_1_1_FN64_SYSTEM_RESET2:
                return psci_forward(host_ctxt);
+       case PSCI_1_0_FN64_SYSTEM_SUSPEND:
+               return psci_system_suspend(func_id, host_ctxt);
        default:
                return psci_0_2_handler(func_id, host_ctxt);
        }