Improve pKVM hypercalls #210
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@qwandor Could you please take a look? |
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src/transport/x86_64/hypercalls.rs
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| macro_rules! __vmcall_impl { |
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Can this just be a simple function rather than a macro? The caller can pass zeroes for any unused parameters, and cast everything to u64.
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Done - use simple function rather than a macro. I've left the macro wrapper so the caller do not have to care about zeroing not used arguments.
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src/transport/x86_64/hypercalls.rs
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| ); | ||
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| core::arch::asm!( |
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There's already a use statement for asm, no need to use the full path here.
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Yeah, thx.
The pKVM hypervisor forwards PKVM_GHC_IOWRITE and PKVM_GHC_IOWREAD to pKVM host for emulation. In such case, guest registers values in RAX, RBX, RCX, RDX and RSI might become visible to the host. To prevent potential unintended information leakage, introduce vmcall macro which zeros not used hyperacall arguments, and use it for PKVM_GHC_IOWRITE/PKVM_GHC_IOWREAD hypercall to make sure that unused RDX or RSI are set to 0.
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The pKVM hypervisor forwards PKVM_GHC_IOWRITE and PKVM_GHC_IOWREAD to pKVM host for emulation. In such case, guest registers values in RAX, RBX, RCX, RDX and RSI might become visible to the host.
To prevent potential unintended information leakage, introduce vmcall macro which zeros not used hyperacall arguments, and use it for PKVM_GHC_IOWRITE/PKVM_GHC_IOWREAD hypercall to make sure that unused RDX or RSI are set to 0.