On 7/21/22 00:21, Sean Christopherson wrote:
On Wed, Jul 20, 2022, Gupta, Pankaj wrote:
+bool __weak kvm_arch_private_mem_supported(struct kvm *kvm)
Use kvm_arch_has_private_mem(), both because "has" makes it obvious this is checking
a flag of sorts, and to align with other helpers of this nature (and with
CONFIG_HAVE_KVM_PRIVATE_MEM).
$ git grep kvm_arch | grep supported | wc -l
0
$ git grep kvm_arch | grep has | wc -l
26
+#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
+ case KVM_MEMORY_ENCRYPT_REG_REGION:
+ case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
+ struct kvm_enc_region region;
+
+ if (!kvm_arch_private_mem_supported(kvm))
+ goto arch_vm_ioctl;
+
+ r = -EFAULT;
+ if (copy_from_user(®ion, argp, sizeof(region)))
+ goto out;
+
+ r = kvm_vm_ioctl_set_encrypted_region(kvm, ioctl, ®ion);
this is to store private region metadata not only the encrypted region?
Correct.
Sorry for not being clear, was suggesting name change of this function from:
"kvm_vm_ioctl_set_encrypted_region" to "kvm_vm_ioctl_set_private_region"
Though I don't have strong reason to change it, I'm fine with this and
Yes, no strong reason, just thought "kvm_vm_ioctl_set_private_region" would
depict the actual functionality :)
this name matches the above kvm_arch_private_mem_supported perfectly.
BTW could not understand this, how "kvm_vm_ioctl_set_encrypted_region"
matches "kvm_arch_private_mem_supported"?
Chao is saying that kvm_vm_ioctl_set_private_region() pairs nicely with
kvm_arch_private_mem_supported(), not that the "encrypted" variant pairs nicely.
I also like using "private" instead of "encrypted", though we should probably
find a different verb than "set", because calling "set_private" when making the
region shared is confusing. I'm struggling to come up with a good alternative
though.
kvm_vm_ioctl_set_memory_region() is already taken by KVM_SET_USER_MEMORY_REGION,
and that also means that anything with "memory_region" in the name is bound to be
confusing.
Hmm, and if we move away from "encrypted", it probably makes sense to pass in
addr+size instead of a kvm_enc_region.
Maybe this?
static int kvm_vm_ioctl_set_or_clear_mem_private(struct kvm *kvm, gpa_t gpa,
gpa_t size, bool set_private)
and then:
#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
case KVM_MEMORY_ENCRYPT_REG_REGION:
case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
bool set = ioctl == KVM_MEMORY_ENCRYPT_REG_REGION;
struct kvm_enc_region region;
if (!kvm_arch_private_mem_supported(kvm))
goto arch_vm_ioctl;
r = -EFAULT;
if (copy_from_user(®ion, argp, sizeof(region)))
goto out;
r = kvm_vm_ioctl_set_or_clear_mem_private(kvm, region.addr,
region.size, set);
break;
}
#endif
I don't love it, so if someone has a better idea...
Maybe you could tag it with cgs for all the confidential guest support
related stuff:
e.g. kvm_vm_ioctl_set_cgs_mem()
bool is_private = ioctl == KVM_MEMORY_ENCRYPT_REG_REGION;
...
kvm_vm_ioctl_set_cgs_mem(, is_private)
