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Move pKVM hypercalls to a submodule.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,83 @@ | ||
| //! Hypercalls for x86-64 pKVM. | ||
| use core::arch::asm; | ||
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||
| /// This CPUID returns the signature and should be used to determine if VM is running under pKVM, | ||
| /// KVM or not. See the Linux header `arch/x86/include/uapi/asm/kvm_para.h`. | ||
| const KVM_CPUID_SIGNATURE: u32 = 0x40000000; | ||
|
|
||
| // See `include/uapi/linux/kvm_para.h`. (These hypercalls numbers can change depending on the | ||
| // upstream progress.) | ||
| const KVM_HC_PKVM_OP: u32 = 20; | ||
| const PKVM_GHC_IOREAD: u32 = KVM_HC_PKVM_OP + 3; | ||
| const PKVM_GHC_IOWRITE: u32 = KVM_HC_PKVM_OP + 4; | ||
|
|
||
| /// Gets the signature CPU ID. | ||
| pub fn cpuid_signature() -> [u8; 4] { | ||
| let signature: u32; | ||
| unsafe { | ||
| // The argument for cpuid is passed via rax and in case of KVM_CPUID_SIGNATURE returned via | ||
| // rbx, rcx and rdx. Ideally using a named argument in inline asm for rbx would be more | ||
| // straightforward, but when "rbx" is directly used LLVM complains that it is used | ||
| // internally. | ||
| // | ||
| // Therefore use r8 instead and push rbx to the stack before making cpuid call, store | ||
| // rbx content to r8 as use it as inline asm output and pop the rbx. | ||
| asm!( | ||
| "push rbx", | ||
| "cpuid", | ||
| "mov r8, rbx", | ||
| "pop rbx", | ||
| in("eax") KVM_CPUID_SIGNATURE, | ||
| out("r8") signature, | ||
| out("rcx") _, | ||
| out("rdx") _, | ||
| ); | ||
| }; | ||
| signature.to_le_bytes() | ||
| } | ||
|
|
||
| /// Asks the hypervisor to perform an IO read at the given physical address. | ||
| pub fn hyp_io_read(address: usize, size: usize) -> u64 { | ||
| // Arguments for vmcall are passed via rax, rbx, rcx and rdx. Ideally using a named argument in | ||
| // the inline asm for rbx would be more straightforward, but when "rbx" is used directly LLVM | ||
| // complains that it is used internally. | ||
| // | ||
| // Therefore use r8 temporary, push rbx to the stack, perform proper call and pop rbx | ||
| // again | ||
| let data; | ||
| unsafe { | ||
| asm!( | ||
| "push rbx", | ||
| "mov rbx, r8", | ||
| "vmcall", | ||
| "pop rbx", | ||
| inout("rax") u64::from(PKVM_GHC_IOREAD) => data, | ||
| in("r8") address, | ||
| in("rcx") size, | ||
| ); | ||
| } | ||
| data | ||
| } | ||
|
|
||
| /// Asks the hypervisor to perform an IO write at the given physical address. | ||
| pub fn hyp_io_write(address: usize, size: usize, data: u64) { | ||
| unsafe { | ||
| // Arguments for vmcall are passed via rax, rbx, rcx and rdx. Ideally using a named argument | ||
| // in the inline asm for rbx would be more straightforward but when "rbx" is used directly | ||
| // used LLVM complains that it is used internally. | ||
| // | ||
| // Therefore use r8 temporary, push rbx to the stack, perform proper call and pop rbx | ||
| // again | ||
| asm!( | ||
| "push rbx", | ||
| "mov rbx, r8", | ||
| "vmcall", | ||
| "pop rbx", | ||
| in("rax") PKVM_GHC_IOWRITE, | ||
| in("r8") address, | ||
| in("rcx") size, | ||
| in("rdx") data, | ||
| ); | ||
| } | ||
| } |