diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-14 10:21:34 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-14 10:21:34 -0700 |
commit | da9803dfd3955bd2f9909d55e23f188ad76dbe58 (patch) | |
tree | 9e4ea42559f82bf46340d91fa3312ea555686cf6 /arch/x86/kvm/svm | |
parent | 6873139ed078bfe0341d4cbb69e5af1b323bf532 (diff) | |
parent | 0ddfb1cf3b6b07c97cff16ea69931d986f9622ee (diff) |
Merge tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SEV-ES support from Borislav Petkov:
"SEV-ES enhances the current guest memory encryption support called SEV
by also encrypting the guest register state, making the registers
inaccessible to the hypervisor by en-/decrypting them on world
switches. Thus, it adds additional protection to Linux guests against
exfiltration, control flow and rollback attacks.
With SEV-ES, the guest is in full control of what registers the
hypervisor can access. This is provided by a guest-host exchange
mechanism based on a new exception vector called VMM Communication
Exception (#VC), a new instruction called VMGEXIT and a shared
Guest-Host Communication Block which is a decrypted page shared
between the guest and the hypervisor.
Intercepts to the hypervisor become #VC exceptions in an SEV-ES guest
so in order for that exception mechanism to work, the early x86 init
code needed to be made able to handle exceptions, which, in itself,
brings a bunch of very nice cleanups and improvements to the early
boot code like an early page fault handler, allowing for on-demand
building of the identity mapping. With that, !KASLR configurations do
not use the EFI page table anymore but switch to a kernel-controlled
one.
The main part of this series adds the support for that new exchange
mechanism. The goal has been to keep this as much as possibly separate
from the core x86 code by concentrating the machinery in two
SEV-ES-specific files:
arch/x86/kernel/sev-es-shared.c
arch/x86/kernel/sev-es.c
Other interaction with core x86 code has been kept at minimum and
behind static keys to minimize the performance impact on !SEV-ES
setups.
Work by Joerg Roedel and Thomas Lendacky and others"
* tag 'x86_seves_for_v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (73 commits)
x86/sev-es: Use GHCB accessor for setting the MMIO scratch buffer
x86/sev-es: Check required CPU features for SEV-ES
x86/efi: Add GHCB mappings when SEV-ES is active
x86/sev-es: Handle NMI State
x86/sev-es: Support CPU offline/online
x86/head/64: Don't call verify_cpu() on starting APs
x86/smpboot: Load TSS and getcpu GDT entry before loading IDT
x86/realmode: Setup AP jump table
x86/realmode: Add SEV-ES specific trampoline entry point
x86/vmware: Add VMware-specific handling for VMMCALL under SEV-ES
x86/kvm: Add KVM-specific VMMCALL handling under SEV-ES
x86/paravirt: Allow hypervisor-specific VMMCALL handling under SEV-ES
x86/sev-es: Handle #DB Events
x86/sev-es: Handle #AC Events
x86/sev-es: Handle VMMCALL Events
x86/sev-es: Handle MWAIT/MWAITX Events
x86/sev-es: Handle MONITOR/MONITORX Events
x86/sev-es: Handle INVD Events
x86/sev-es: Handle RDPMC Events
x86/sev-es: Handle RDTSC(P) Events
...
Diffstat (limited to 'arch/x86/kvm/svm')
-rw-r--r-- | arch/x86/kvm/svm/nested.c | 47 | ||||
-rw-r--r-- | arch/x86/kvm/svm/svm.c | 2 |
2 files changed, 35 insertions, 14 deletions
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index e90bc436f584..598a769f1961 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1062,10 +1062,14 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, struct vmcb *hsave = svm->nested.hsave; struct vmcb __user *user_vmcb = (struct vmcb __user *) &user_kvm_nested_state->data.svm[0]; - struct vmcb_control_area ctl; - struct vmcb_save_area save; + struct vmcb_control_area *ctl; + struct vmcb_save_area *save; + int ret; u32 cr0; + BUILD_BUG_ON(sizeof(struct vmcb_control_area) + sizeof(struct vmcb_save_area) > + KVM_STATE_NESTED_SVM_VMCB_SIZE); + if (kvm_state->format != KVM_STATE_NESTED_FORMAT_SVM) return -EINVAL; @@ -1097,13 +1101,22 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, return -EINVAL; if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE) return -EINVAL; - if (copy_from_user(&ctl, &user_vmcb->control, sizeof(ctl))) - return -EFAULT; - if (copy_from_user(&save, &user_vmcb->save, sizeof(save))) - return -EFAULT; - if (!nested_vmcb_check_controls(&ctl)) - return -EINVAL; + ret = -ENOMEM; + ctl = kzalloc(sizeof(*ctl), GFP_KERNEL); + save = kzalloc(sizeof(*save), GFP_KERNEL); + if (!ctl || !save) + goto out_free; + + ret = -EFAULT; + if (copy_from_user(ctl, &user_vmcb->control, sizeof(*ctl))) + goto out_free; + if (copy_from_user(save, &user_vmcb->save, sizeof(*save))) + goto out_free; + + ret = -EINVAL; + if (!nested_vmcb_check_controls(ctl)) + goto out_free; /* * Processor state contains L2 state. Check that it is @@ -1111,15 +1124,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, */ cr0 = kvm_read_cr0(vcpu); if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW)) - return -EINVAL; + goto out_free; /* * Validate host state saved from before VMRUN (see * nested_svm_check_permissions). * TODO: validate reserved bits for all saved state. */ - if (!(save.cr0 & X86_CR0_PG)) - return -EINVAL; + if (!(save->cr0 & X86_CR0_PG)) + goto out_free; /* * All checks done, we can enter guest mode. L1 control fields @@ -1128,10 +1141,10 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, * contains saved L1 state. */ copy_vmcb_control_area(&hsave->control, &svm->vmcb->control); - hsave->save = save; + hsave->save = *save; svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa; - load_nested_vmcb_control(svm, &ctl); + load_nested_vmcb_control(svm, ctl); nested_prepare_vmcb_control(svm); if (!nested_svm_vmrun_msrpm(svm)) @@ -1139,7 +1152,13 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, out_set_gif: svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET)); - return 0; + + ret = 0; +out_free: + kfree(save); + kfree(ctl); + + return ret; } struct kvm_x86_nested_ops svm_nested_ops = { diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index dec6d5bc603c..9709c98d0d6c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4176,6 +4176,8 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = { static int __init svm_init(void) { + __unused_size_checks(); + return kvm_init(&svm_init_ops, sizeof(struct vcpu_svm), __alignof__(struct vcpu_svm), THIS_MODULE); } |