move encrypt_op{_sev} into system ioctls

[jakecorrenti]

Summary of the PR

According to the KVM API, KVM_MEMORY_ENCRYPT_OP is labeled as a system ioctl. However, it is currently treated as a VM ioctl. There are no functional changes to the code, only the location and function signature.

Requirements

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  summary and max 75 characters for each description line.
• All added/changed functionality has a corresponding unit/integration
  test.
• All added/changed public-facing functionality has entries in the "Upcoming
  Release" section of CHANGELOG.md (if no such section exists, please create one).
• Any newly added unsafe code is properly documented.

[jakecorrenti]

Just for reference, this is the documentation that states the KVM API now uses MEMORY_ENCRYPT_OP as a system ioctl: https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt

[roypat]

Sorry for the late review, my GitHub search was not showing this one for some reason :(

[roypat]

Could you add the PR number here?

Suggested change

	- Changed `encrypt_op` and `encrypt_op_sev` to system ioctls to be in line
	- [[#259](https://github.com/rust-vmm/kvm-ioctls/pull/259)] Changed `encrypt_op` and `encrypt_op_sev` to system ioctls to be in line

[roypat]

I'm not familiar with AMD-SEV, but if this is a system ioctl, shouldn't it be issued on the KVM fd? e.g.

Suggested change

	pub unsafe fn encrypt_op<T>(&self, fd: &impl AsRawFd, op: *mut T) -> Result<()> {
	let ret = ioctl_with_mut_ptr(fd, KVM_MEMORY_ENCRYPT_OP(), op);
	pub unsafe fn encrypt_op<T>(&self, op: *mut T) -> Result<()> {
	let ret = ioctl_with_mut_ptr(&self.kvm, KVM_MEMORY_ENCRYPT_OP(), op);

[jakecorrenti]

Yes, I believe you're right. It was brought to my attention that I was referencing stale documentation. However, the changes to the ioctl should be so that it is both a vm ioctl and a vcpu ioctl, so that requires an update on my end.

[rbradford]

Just for reference, this is the documentation that states the KVM API now uses MEMORY_ENCRYPT_OP as a system ioctl: https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt

Not sure how old that documentation is - but v6.9 - the last release version shows this is a vm type ioctl - https://elixir.bootlin.com/linux/v6.9/source/Documentation/virt/kvm/api.rst#L4732

The wrong label was fixed in torvalds/linux@46ca9ee

[rbradford]

I identified the issue as a case of stale content on kernel.org when the directory was renamed by

commit 2f5947dfcaecb99f2dd559156eecbeb7b95e4c02
Author: Christoph Hellwig <[email protected]>
Date:   Wed Jul 24 09:24:49 2019 +0200

    Documentation: move Documentation/virtual to Documentation/virt
    
    Renaming docs seems to be en vogue at the moment, so fix on of the
    grossly misnamed directories.  We usually never use "virtual" as
    a shortcut for virtualization in the kernel, but always virt,
    as seen in the virt/ top-level directory.  Fix up the documentation
    to match that.
    
    Fixes: ed16648eb5b8 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
    Signed-off-by: Christoph Hellwig <[email protected]>
    Signed-off-by: Paolo Bonzini <[email protected]>

Compare - https://www.kernel.org/doc/Documentation/virt/kvm/api.txt (current) with https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt (stale)

I have contacted the kernel.org team to highlight the issue.

[jakecorrenti]

I identified the issue as a case of stale content on kernel.org when the directory was renamed by

commit 2f5947dfcaecb99f2dd559156eecbeb7b95e4c02
Author: Christoph Hellwig [email protected]
Date: Wed Jul 24 09:24:49 2019 +0200

Documentation: move Documentation/virtual to Documentation/virt

Renaming docs seems to be en vogue at the moment, so fix on of the
grossly misnamed directories.  We usually never use "virtual" as
a shortcut for virtualization in the kernel, but always virt,
as seen in the virt/ top-level directory.  Fix up the documentation
to match that.

Fixes: ed16648eb5b8 ("Move kvm, uml, and lguest subdirectories under a common "virtual" directory, I.E:")
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Compare - https://www.kernel.org/doc/Documentation/virt/kvm/api.txt (current) with https://www.kernel.org/doc/Documentation/virtual/kvm/api.txt (stale)

I have contacted the kernel.org team to highlight the issue.

Thank you for doing that.

However, I still see this change being needed (with some adjustments). Intel TDX (and I think Arm CCA as well) is repurposing this ioctl and it is used on both Vm fd's and Vcpu fd's. Intel's documentation about it can be located here.