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| author | Brijesh Singh <brijesh.singh@amd.com> | 2017-10-20 17:30:58 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-11-07 17:36:00 +0300 |
| commit | 4716276184ec67a123a4eab81609a0688b1d650b (patch) | |
| tree | 53dc65ef1398d44ad05e62f960bf995e59088d79 /arch/x86/kernel/kvm.c | |
| parent | ac26963a1175c813e3ed21c0d2435b083173136e (diff) | |
| download | linux-4716276184ec67a123a4eab81609a0688b1d650b.tar.xz | |
X86/KVM: Decrypt shared per-cpu variables when SEV is active
When SEV is active, guest memory is encrypted with a guest-specific key, a
guest memory region shared with the hypervisor must be mapped as decrypted
before it can be shared.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20171020143059.3291-17-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/kernel/kvm.c')
| -rw-r--r-- | arch/x86/kernel/kvm.c | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 8bb9594d0761..3df743b60c80 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -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 |