linux-kernel - Re: [PATCH 4/6] KVM: selftests: Make Hyper-V guest OS ID common

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Message-ID: <Y2lXld6G+Hp0FW3A@google.com>
Date:   Mon, 7 Nov 2022 11:08:05 -0800
From:   David Matlack <dmatlack@...gle.com>
To:     Vipin Sharma <vipinsh@...gle.com>
Cc:     seanjc@...gle.com, pbonzini@...hat.com, vkuznets@...hat.com,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] KVM: selftests: Make Hyper-V guest OS ID common

On Fri, Nov 04, 2022 at 09:57:02PM -0700, Vipin Sharma wrote:
> Make guest OS ID calculation common to all hyperv tests and similar to
> hv_generate_guest_id().

This commit makes the HV_LINUX_VENDOR_ID and adds LINUX_VERSION_CODE
to existing tests. Can you split out the latter to a separate commit?
Also what's the reason to add LINUX_VERSION_CODE to the mix?

> 
> Signed-off-by: Vipin Sharma <vipinsh@...gle.com>
> ---
>  tools/testing/selftests/kvm/include/x86_64/hyperv.h  | 10 ++++++++++
>  tools/testing/selftests/kvm/x86_64/hyperv_clock.c    |  2 +-
>  tools/testing/selftests/kvm/x86_64/hyperv_features.c |  6 ++----
>  tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c |  2 +-
>  4 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86_64/hyperv.h b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> index 075fd29071a6..9d8c325af1d9 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> @@ -9,6 +9,10 @@
>  #ifndef SELFTEST_KVM_HYPERV_H
>  #define SELFTEST_KVM_HYPERV_H
>  
> +#include <linux/version.h>
> +
> +#define HV_LINUX_VENDOR_ID			0x8100
> +
>  #define HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS	0x40000000
>  #define HYPERV_CPUID_INTERFACE			0x40000001
>  #define HYPERV_CPUID_VERSION			0x40000002
> @@ -189,4 +193,10 @@
>  /* hypercall options */
>  #define HV_HYPERCALL_FAST_BIT		BIT(16)
>  
> +static inline uint64_t hv_linux_guest_id(void)
> +{
> +	return ((uint64_t)HV_LINUX_VENDOR_ID << 48) |
> +	       ((uint64_t)LINUX_VERSION_CODE << 16);

This can be a compile-time constant (i.e. macro).

> +}
> +
>  #endif /* !SELFTEST_KVM_HYPERV_H */
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_clock.c b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
> index d576bc8ce823..f9112c5dc3f7 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_clock.c
> @@ -104,7 +104,7 @@ static void guest_main(struct ms_hyperv_tsc_page *tsc_page, vm_paddr_t tsc_page_
>  
>  	/* Set Guest OS id to enable Hyper-V emulation */
>  	GUEST_SYNC(1);
> -	wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48);
> +	wrmsr(HV_X64_MSR_GUEST_OS_ID, hv_linux_guest_id());
>  	GUEST_SYNC(2);
>  
>  	check_tsc_msr_rdtsc();
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_features.c b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> index 6b443ce456b6..b5a42cf1ad9d 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> @@ -13,8 +13,6 @@
>  #include "processor.h"
>  #include "hyperv.h"
>  
> -#define LINUX_OS_ID ((u64)0x8100 << 48)
> -
>  static inline uint8_t hypercall(u64 control, vm_vaddr_t input_address,
>  				vm_vaddr_t output_address, uint64_t *hv_status)
>  {
> @@ -71,7 +69,7 @@ static void guest_hcall(vm_vaddr_t pgs_gpa, struct hcall_data *hcall)
>  
>  	GUEST_ASSERT(hcall->control);
>  
> -	wrmsr(HV_X64_MSR_GUEST_OS_ID, LINUX_OS_ID);
> +	wrmsr(HV_X64_MSR_GUEST_OS_ID, hv_linux_guest_id());
>  	wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
>  
>  	if (!(hcall->control & HV_HYPERCALL_FAST_BIT)) {
> @@ -169,7 +167,7 @@ static void guest_test_msrs_access(void)
>  			 */
>  			msr->idx = HV_X64_MSR_GUEST_OS_ID;
>  			msr->write = 1;
> -			msr->write_val = LINUX_OS_ID;
> +			msr->write_val = hv_linux_guest_id();
>  			msr->available = 1;
>  			break;
>  		case 3:
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> index a380ad7bb9b3..2c13a144b04c 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> @@ -69,7 +69,7 @@ static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
>  
>  	GUEST_SYNC(1);
>  
> -	wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48);
> +	wrmsr(HV_X64_MSR_GUEST_OS_ID, hv_linux_guest_id());
>  
>  	GUEST_ASSERT(svm->vmcb_gpa);
>  	/* Prepare for L2 execution. */
> -- 
> 2.38.1.273.g43a17bfeac-goog
>