Add kvm guest memfd related capabilities #288
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The capabilities are required to properly setup a guest_memfd to provide better host and guest memory isolation. The memory attributes capability returns an integer with each bits representing different configs. For example, the return integer & KVM_MEMORY_ATTRIBUTE_PRIVATE > 0 means the vm is capable of setting memory pages to private. Signed-off-by: Sida Chen <[email protected]>
Signed-off-by: Sida Chen <[email protected]>
Signed-off-by: Sida Chen <[email protected]>
Signed-off-by: Sida Chen <[email protected]>
Signed-off-by: Sida Chen <[email protected]>
KeyboardNerd
requested review from
acatangiu,
andreeaflorescu,
lauralt,
sameo,
roypat and
ShadowCurse
as code owners
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It's a continued discussion from |
| #[test] | ||
| fn test_check_extension_int() { | ||
| let kvm = Kvm::new().unwrap(); | ||
| let vm = kvm.create_vm().unwrap(); | ||
| assert!(vm.check_extension_int(Cap::MpState) > 0); | ||
| } |
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Since test_check_extension_raw exists, in my view test_check_extension_int is not necessary, it's just a wrapper on check_extension_raw. This test is just duplicating existing code :)
| fn test_check_extension_raw() { | ||
| let kvm = Kvm::new().unwrap(); | ||
| let vm = kvm.create_vm().unwrap(); | ||
| assert!(vm.check_extension_raw(Cap::MpState as c_ulong) > 0); |
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IMHO this is literally a check_extension test which gets expanded, if we intend to test check_extension_raw positively, we can do something like assert_eq!(vm.check_extension_raw(Cap::MaxVcpus), 1024); here to state that we want an int which its value matters.
Or else we just do negative test here :)
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1024 here is for RISC-V, as of the other two archs, we will need to set its value accordingly
| /// use kvm_ioctls::Cap; | ||
| /// | ||
| /// let kvm = Kvm::new().unwrap(); | ||
| /// assert!(kvm.check_extension_raw(Cap::MaxVcpus as c_ulong) > 0); |
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This is the wrong function to call here, as it does the system-wide extension check, instead of the VM-level extension check. If you fix this, you can also remove the unittest you added, because they're the same as these doctests :)
| /// ``` | ||
| /// extern crate kvm_bindings; | ||
| /// | ||
| /// # use kvm_bindings::{KVM_MEMORY_ATTRIBUTE_PRIVATE}; |
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No need for this import, since the final version of the code is checking the MaxVcpus capability
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Could you also squash all the commits into one? |
Summary of the PR
The capabilities are required to properly setup a guest_memfd to provide better host and guest memory isolation. The memory attributes capability returns an integer with each bits representing different configs. For example, the return integer & KVM_MEMORY_ATTRIBUTE_PRIVATE > 0 means the vm is capable of setting memory pages to private.
Requirements
Before submitting your PR, please make sure you addressed the following
requirements:
git commit -s), and the commit message has max 60 characters for thesummary and max 75 characters for each description line.
test.
Release" section of CHANGELOG.md (if no such section exists, please create one).
unsafecode is properly documented.