Re: [PATCH v8 23/40] KVM: x86: move lookup of indexed CPUID leafs to helper

Venu Busireddy
2022-01-06T18:47:15Z

On 2021-12-10 09:43:15 -0600, Brijesh Singh wrote:
> From: Michael Roth <michael.roth@amd.com>
>
> Determining which CPUID leafs have significant ECX/index values is
> also needed by guest kernel code when doing SEV-SNP-validated CPUID
> lookups. Move this to common code to keep future updates in sync.
>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>

Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>

> ---
> arch/x86/include/asm/cpuid.h | 26 ++++++++++++++++++++++++++
> arch/x86/kvm/cpuid.c | 17 ++---------------
> 2 files changed, 28 insertions(+), 15 deletions(-)
> create mode 100644 arch/x86/include/asm/cpuid.h
>
> diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
> new file mode 100644
> index 000000000000..61426eb1f665
> --- /dev/null
> +++ b/arch/x86/include/asm/cpuid.h
> @@ -0,0 +1,26 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_CPUID_H
> +#define _ASM_X86_CPUID_H
> +
> +static __always_inline bool cpuid_function_is_indexed(u32 function)
> +{
> + switch (function) {
> + case 4:
> + case 7:
> + case 0xb:
> + case 0xd:
> + case 0xf:
> + case 0x10:
> + case 0x12:
> + case 0x14:
> + case 0x17:
> + case 0x18:
> + case 0x1f:
> + case 0x8000001d:
> + return true;
> + }
> +
> + return false;
> +}
> +
> +#endif /* _ASM_X86_CPUID_H */
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 07e9215e911d..6b99e8e87480 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -19,6 +19,7 @@
> #include <asm/user.h>
> #include <asm/fpu/xstate.h>
> #include <asm/sgx.h>
> +#include <asm/cpuid.h>
> #include "cpuid.h"
> #include "lapic.h"
> #include "mmu.h"
> @@ -626,22 +627,8 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
> cpuid_count(entry->function, entry->index,
> &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
>
> - switch (function) {
> - case 4:
> - case 7:
> - case 0xb:
> - case 0xd:
> - case 0xf:
> - case 0x10:
> - case 0x12:
> - case 0x14:
> - case 0x17:
> - case 0x18:
> - case 0x1f:
> - case 0x8000001d:
> + if (cpuid_function_is_indexed(function))
> entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> - break;
> - }
>
> return entry;
> }
> --
> 2.25.1
>