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arch: Support fine-grained CPUID compatibility check

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To support different CPUID entry semantics, we now allow to
specify the compatible condition for each feature entry. Most entries
are considered compatible when they are "bitwise subset", with few
exceptions: 1. "equal", e.g. EBX/ECX/EDX of leaf `0x4000_0000` (KVM
CPUID SIGNATURE); 2. "smaller or equal as a number", e.g. EAX of leaf
`0x7` and leaf `0x4000_0000`;

Signed-off-by: Bo Chen <chen.bo@intel.com>
This commit is contained in:
Bo Chen 2021-07-27 16:32:11 -07:00 committed by Sebastien Boeuf
parent ca09638491
commit 2723995cfa
1 changed files with 68 additions and 9 deletions
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77
arch/src/x86_64/mod.rs
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@ -341,10 +341,18 @@ impl CpuidPatch {
}
}
#[derive(Debug)]
enum CpuidCompatibleCheck {
BitwiseSubset, // bitwise subset
Equal, // equal in value
NumNotGreater, // smaller or equal as a number
}
pub struct CpuidFeatureEntry {
pub function: u32,
pub index: u32,
pub feature_reg: CpuidReg,
function: u32,
index: u32,
feature_reg: CpuidReg,
compatible_check: CpuidCompatibleCheck,
}
impl CpuidFeatureEntry {
@ -357,71 +365,109 @@ impl CpuidFeatureEntry {
function: 1,
index: 0,
feature_reg: CpuidReg::ECX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 1,
index: 0,
feature_reg: CpuidReg::EDX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
// Leaf 0x7, EAX/EBX/ECX/EDX, extended features
CpuidFeatureEntry {
function: 7,
index: 0,
feature_reg: CpuidReg::EAX,
compatible_check: CpuidCompatibleCheck::NumNotGreater,
},
CpuidFeatureEntry {
function: 7,
index: 0,
feature_reg: CpuidReg::EBX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 7,
index: 0,
feature_reg: CpuidReg::ECX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 7,
index: 0,
feature_reg: CpuidReg::EDX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
// Leaf 0x7 subleaf 0x1, EAX, extended features
CpuidFeatureEntry {
function: 7,
index: 1,
feature_reg: CpuidReg::EAX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
// Leaf 0x8000_0001, ECX/EDX, CPUID features bits
CpuidFeatureEntry {
function: 0x8000_0001,
index: 0,
feature_reg: CpuidReg::ECX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 0x8000_0001,
index: 0,
feature_reg: CpuidReg::EDX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
// KVM CPUID bits: https://www.kernel.org/doc/html/latest/virt/kvm/cpuid.html
// Leaf 0x4000_0000, EAX/EBX/ECX/EDX, KVM CPUID SIGNATURE
CpuidFeatureEntry {
function: 0x4000_0000,
index: 0,
feature_reg: CpuidReg::EAX,
compatible_check: CpuidCompatibleCheck::NumNotGreater,
},
CpuidFeatureEntry {
function: 0x4000_0000,
index: 0,
feature_reg: CpuidReg::EBX,
compatible_check: CpuidCompatibleCheck::Equal,
},
CpuidFeatureEntry {
function: 0x4000_0000,
index: 0,
feature_reg: CpuidReg::ECX,
compatible_check: CpuidCompatibleCheck::Equal,
},
CpuidFeatureEntry {
function: 0x4000_0000,
index: 0,
feature_reg: CpuidReg::EDX,
compatible_check: CpuidCompatibleCheck::Equal,
},
// Leaf 0x4000_0001, EAX/EBX/ECX/EDX, KVM CPUID features
CpuidFeatureEntry {
function: 0x4000_0001,
index: 0,
feature_reg: CpuidReg::EAX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 0x4000_0001,
index: 0,
feature_reg: CpuidReg::EBX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 0x4000_0001,
index: 0,
feature_reg: CpuidReg::ECX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
CpuidFeatureEntry {
function: 0x4000_0001,
index: 0,
feature_reg: CpuidReg::EDX,
compatible_check: CpuidCompatibleCheck::BitwiseSubset,
},
]
}
@ -477,14 +523,27 @@ impl CpuidFeatureEntry {
.zip(dest_vm_features.iter())
.enumerate()
{
let different_feature_bits = src_vm_feature ^ dest_vm_feature;
let src_vm_feature_bits_only = different_feature_bits & src_vm_feature;
if src_vm_feature_bits_only != 0 {
let entry = &feature_entry_list[i];
let entry_compatible;
match entry.compatible_check {
CpuidCompatibleCheck::BitwiseSubset => {
let different_feature_bits = src_vm_feature ^ dest_vm_feature;
let src_vm_feature_bits_only = different_feature_bits & src_vm_feature;
entry_compatible = src_vm_feature_bits_only == 0;
}
CpuidCompatibleCheck::Equal => {
entry_compatible = src_vm_feature == dest_vm_feature;
}
CpuidCompatibleCheck::NumNotGreater => {
entry_compatible = src_vm_feature <= dest_vm_feature;
}
};
if !entry_compatible {
error!(
"Detected incompatible CPUID entry: leaf={:#02x} (subleaf={:#02x}), register='{:?}', \
source VM feature='{:#04x}', destination VM feature'{:#04x}'.",
feature_entry_list[i].function, feature_entry_list[i].index, feature_entry_list[i].feature_reg,
src_vm_feature, dest_vm_feature
compatilbe_check='{:?}', source VM feature='{:#04x}', destination VM feature'{:#04x}'.",
entry.function, entry.index, entry.feature_reg,
entry.compatible_check, src_vm_feature, dest_vm_feature
);
compatible = false;