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| author | Michael Brown <mcb30@ipxe.org> | 2024-07-31 16:35:31 +0100 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2024-08-01 12:49:48 +0100 |
| commit | 121d96b903b221e2c63fa0fc5a8901dc24645a47 (patch) | |
| tree | 78a922651fadcc5c70218b7fd89ced8934c6452d | |
| parent | c117e6a4811efa057dc70426d58a8dab75245862 (diff) | |
| download | ipxe-121d96b903b221e2c63fa0fc5a8901dc24645a47.zip ipxe-121d96b903b221e2c63fa0fc5a8901dc24645a47.tar.gz ipxe-121d96b903b221e2c63fa0fc5a8901dc24645a47.tar.bz2 | |
[cpuid] Allow reading hypervisor CPUID leaves
Hypervisors typically intercept CPUID leaves in the range 0x40000000
to 0x400000ff, with leaf 0x40000000 returning the maximum supported
function within this range in register %eax.
iPXE currently masks off bit 30 from the requested CPUID leaf when
checking to see if a function is supported, which causes this check to
read from leaf 0x00000000 instead of 0x40000000.
Fix by including bit 30 within the mask.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
| -rw-r--r-- | src/arch/x86/core/cpuid.c | 4 | ||||
| -rw-r--r-- | src/arch/x86/include/ipxe/cpuid.h | 3 |
2 files changed, 5 insertions, 2 deletions
diff --git a/src/arch/x86/core/cpuid.c b/src/arch/x86/core/cpuid.c index 1a7c93e..b7d9fb6 100644 --- a/src/arch/x86/core/cpuid.c +++ b/src/arch/x86/core/cpuid.c @@ -84,8 +84,8 @@ int cpuid_supported ( uint32_t function ) { return rc; /* Find highest supported function number within this family */ - cpuid ( ( function & CPUID_EXTENDED ), 0, &max_function, &discard_b, - &discard_c, &discard_d ); + cpuid ( ( function & ( CPUID_EXTENDED | CPUID_HYPERVISOR ) ), 0, + &max_function, &discard_b, &discard_c, &discard_d ); /* Fail if maximum function number is meaningless (e.g. if we * are attempting to call an extended function on a CPU which diff --git a/src/arch/x86/include/ipxe/cpuid.h b/src/arch/x86/include/ipxe/cpuid.h index 90d1bf0..99b91c5 100644 --- a/src/arch/x86/include/ipxe/cpuid.h +++ b/src/arch/x86/include/ipxe/cpuid.h @@ -33,6 +33,9 @@ struct x86_features { /** CPUID extended function */ #define CPUID_EXTENDED 0x80000000UL +/** CPUID hypervisor function */ +#define CPUID_HYPERVISOR 0x40000000UL + /** Get vendor ID and largest standard function */ #define CPUID_VENDOR_ID 0x00000000UL |