X86/KVM: Decrypt shared per-cpu variables when SEV is active (47162761) · Commits · 戴 / test

arch/x86/kernel/kvm.c

+37 −3

Original line number	Diff line number	Diff line
		@@ -75,8 +75,8 @@ static int parse_no_kvmclock_vsyscall(char *arg)

		early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);

		static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
		static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
		static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
		static DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64);
		static int has_steal_clock = 0;

		/*
		@@ -312,7 +312,7 @@ static void kvm_register_steal_time(void)
		cpu, (unsigned long long) slow_virt_to_phys(st));
		}

		static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
		static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;

		static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
		{
		@@ -426,9 +426,42 @@ void kvm_disable_steal_time(void)
		wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
		}

		static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
		{
		early_set_memory_decrypted((unsigned long) ptr, size);
		}

		/*
		* Iterate through all possible CPUs and map the memory region pointed
		* by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
		*
		* Note: we iterate through all possible CPUs to ensure that CPUs
		* hotplugged will have their per-cpu variable already mapped as
		* decrypted.
		*/
		static void __init sev_map_percpu_data(void)
		{
		int cpu;

		if (!sev_active())
		return;

		for_each_possible_cpu(cpu) {
		__set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
		__set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
		__set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
		}
		}

		#ifdef CONFIG_SMP
		static void __init kvm_smp_prepare_boot_cpu(void)
		{
		/*
		* Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
		* shares the guest physical address with the hypervisor.
		*/
		sev_map_percpu_data();

		kvm_guest_cpu_init();
		native_smp_prepare_boot_cpu();
		kvm_spinlock_init();
		@@ -496,6 +529,7 @@ void __init kvm_guest_init(void)
		kvm_cpu_online, kvm_cpu_down_prepare) < 0)
		pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n");
		#else
		sev_map_percpu_data();
		kvm_guest_cpu_init();
		#endif

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