Re: [PATCH v2 03/14] KVM: SVM: Move SEV module params/variables to sev.c

Brijesh Singh
2021-01-14T21:00:18Z

On 1/13/21 6:36 PM, Sean Christopherson wrote:
> Unconditionally invoke sev_hardware_setup() when configuring SVM and
> handle clearing the module params/variable 'sev' and 'sev_es' in
> sev_hardware_setup(). This allows making said variables static within
> sev.c and reduces the odds of a collision with guest code, e.g. the guest
> side of things has already laid claim to 'sev_enabled'.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/svm/sev.c | 11 +++++++++++
> arch/x86/kvm/svm/svm.c | 15 +--------------
> arch/x86/kvm/svm/svm.h | 2 --
> 3 files changed, 12 insertions(+), 16 deletions(-)

Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>

>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 0eeb6e1b803d..8ba93b8fa435 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -27,6 +27,14 @@
>
> #define __ex(x) __kvm_handle_fault_on_reboot(x)
>
> +/* enable/disable SEV support */
> +static int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> +module_param(sev, int, 0444);
> +
> +/* enable/disable SEV-ES support */
> +static int sev_es = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> +module_param(sev_es, int, 0444);
> +
> static u8 sev_enc_bit;
> static int sev_flush_asids(void);
> static DECLARE_RWSEM(sev_deactivate_lock);
> @@ -1249,6 +1257,9 @@ void __init sev_hardware_setup(void)
> bool sev_es_supported = false;
> bool sev_supported = false;
>
> + if (!IS_ENABLED(CONFIG_KVM_AMD_SEV) || !sev)
> + goto out;
> +
> /* Does the CPU support SEV? */
> if (!boot_cpu_has(X86_FEATURE_SEV))
> goto out;
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index ccf52c5531fb..f89f702b2a58 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -189,14 +189,6 @@ module_param(vls, int, 0444);
> static int vgif = true;
> module_param(vgif, int, 0444);
>
> -/* enable/disable SEV support */
> -int sev = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> -module_param(sev, int, 0444);
> -
> -/* enable/disable SEV-ES support */
> -int sev_es = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> -module_param(sev_es, int, 0444);
> -
> bool __read_mostly dump_invalid_vmcb;
> module_param(dump_invalid_vmcb, bool, 0644);
>
> @@ -976,12 +968,7 @@ static __init int svm_hardware_setup(void)
> kvm_enable_efer_bits(EFER_SVME | EFER_LMSLE);
> }
>
> - if (IS_ENABLED(CONFIG_KVM_AMD_SEV) && sev) {
> - sev_hardware_setup();
> - } else {
> - sev = false;
> - sev_es = false;
> - }
> + sev_hardware_setup();
>
> svm_adjust_mmio_mask();
>
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index 0fe874ae5498..8e169835f52a 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -408,8 +408,6 @@ static inline bool gif_set(struct vcpu_svm *svm)
> #define MSR_CR3_LONG_MBZ_MASK 0xfff0000000000000U
> #define MSR_INVALID 0xffffffffU
>
> -extern int sev;
> -extern int sev_es;
> extern bool dump_invalid_vmcb;
>
> u32 svm_msrpm_offset(u32 msr);