2021-01-14 01:01:23

by Sean Christopherson

[permalink] [raw]
Subject: [PATCH v2 08/14] KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y

Define sev_enabled and sev_es_enabled as 'false' and explicitly #ifdef
out all of sev_hardware_setup() if CONFIG_KVM_AMD_SEV=n. This kills
three birds at once:

- Makes sev_enabled and sev_es_enabled off by default if
CONFIG_KVM_AMD_SEV=n. Previously, they could be on by default if
CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y, regardless of KVM SEV
support.

- Hides the sev and sev_es module params when CONFIG_KVM_AMD_SEV=n.

- Resolves a false positive -Wnonnull in __sev_recycle_asids() that is
currently masked by the equivalent IS_ENABLED(CONFIG_KVM_AMD_SEV)
check in svm_sev_enabled(), which will be dropped in a future patch.

Cc: Tom Lendacky <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
---
arch/x86/kvm/svm/sev.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index a024edabaca5..02a66008e9b9 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -28,12 +28,17 @@
#define __ex(x) __kvm_handle_fault_on_reboot(x)

/* enable/disable SEV support */
+#ifdef CONFIG_KVM_AMD_SEV
static bool sev_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
module_param_named(sev, sev_enabled, bool, 0444);

/* enable/disable SEV-ES support */
static bool sev_es_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
module_param_named(sev_es, sev_es_enabled, bool, 0444);
+#else
+#define sev_enabled false
+#define sev_es_enabled false
+#endif /* CONFIG_KVM_AMD_SEV */

static u8 sev_enc_bit;
static int sev_flush_asids(void);
@@ -1253,11 +1258,12 @@ void sev_vm_destroy(struct kvm *kvm)

void __init sev_hardware_setup(void)
{
+#ifdef CONFIG_KVM_AMD_SEV
unsigned int eax, ebx, ecx, edx;
bool sev_es_supported = false;
bool sev_supported = false;

- if (!IS_ENABLED(CONFIG_KVM_AMD_SEV) || !sev_enabled)
+ if (!sev_enabled)
goto out;

/* Does the CPU support SEV? */
@@ -1311,6 +1317,7 @@ void __init sev_hardware_setup(void)
out:
sev_enabled = sev_supported;
sev_es_enabled = sev_es_supported;
+#endif
}

void sev_hardware_teardown(void)
--
2.30.0.284.gd98b1dd5eaa7-goog


2021-01-14 20:59:58

by Tom Lendacky

[permalink] [raw]
Subject: Re: [PATCH v2 08/14] KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y

On 1/13/21 6:37 PM, Sean Christopherson wrote:
> Define sev_enabled and sev_es_enabled as 'false' and explicitly #ifdef
> out all of sev_hardware_setup() if CONFIG_KVM_AMD_SEV=n. This kills
> three birds at once:
>
> - Makes sev_enabled and sev_es_enabled off by default if
> CONFIG_KVM_AMD_SEV=n. Previously, they could be on by default if
> CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y, regardless of KVM SEV
> support.
>
> - Hides the sev and sev_es module params when CONFIG_KVM_AMD_SEV=n.
>
> - Resolves a false positive -Wnonnull in __sev_recycle_asids() that is
> currently masked by the equivalent IS_ENABLED(CONFIG_KVM_AMD_SEV)
> check in svm_sev_enabled(), which will be dropped in a future patch.
>
> Cc: Tom Lendacky <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>

Reviewed by: Tom Lendacky <[email protected]>

> ---
> arch/x86/kvm/svm/sev.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index a024edabaca5..02a66008e9b9 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -28,12 +28,17 @@
> #define __ex(x) __kvm_handle_fault_on_reboot(x)
>
> /* enable/disable SEV support */
> +#ifdef CONFIG_KVM_AMD_SEV
> static bool sev_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> module_param_named(sev, sev_enabled, bool, 0444);
>
> /* enable/disable SEV-ES support */
> static bool sev_es_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> module_param_named(sev_es, sev_es_enabled, bool, 0444);
> +#else
> +#define sev_enabled false
> +#define sev_es_enabled false
> +#endif /* CONFIG_KVM_AMD_SEV */
>
> static u8 sev_enc_bit;
> static int sev_flush_asids(void);
> @@ -1253,11 +1258,12 @@ void sev_vm_destroy(struct kvm *kvm)
>
> void __init sev_hardware_setup(void)
> {
> +#ifdef CONFIG_KVM_AMD_SEV
> unsigned int eax, ebx, ecx, edx;
> bool sev_es_supported = false;
> bool sev_supported = false;
>
> - if (!IS_ENABLED(CONFIG_KVM_AMD_SEV) || !sev_enabled)
> + if (!sev_enabled)
> goto out;
>
> /* Does the CPU support SEV? */
> @@ -1311,6 +1317,7 @@ void __init sev_hardware_setup(void)
> out:
> sev_enabled = sev_supported;
> sev_es_enabled = sev_es_supported;
> +#endif
> }
>
> void sev_hardware_teardown(void)
>

2021-01-15 01:53:42

by Brijesh Singh

[permalink] [raw]
Subject: Re: [PATCH v2 08/14] KVM: SVM: Condition sev_enabled and sev_es_enabled on CONFIG_KVM_AMD_SEV=y


On 1/13/21 6:37 PM, Sean Christopherson wrote:
> Define sev_enabled and sev_es_enabled as 'false' and explicitly #ifdef
> out all of sev_hardware_setup() if CONFIG_KVM_AMD_SEV=n. This kills
> three birds at once:
>
> - Makes sev_enabled and sev_es_enabled off by default if
> CONFIG_KVM_AMD_SEV=n. Previously, they could be on by default if
> CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y, regardless of KVM SEV
> support.
>
> - Hides the sev and sev_es module params when CONFIG_KVM_AMD_SEV=n.
>
> - Resolves a false positive -Wnonnull in __sev_recycle_asids() that is
> currently masked by the equivalent IS_ENABLED(CONFIG_KVM_AMD_SEV)
> check in svm_sev_enabled(), which will be dropped in a future patch.
>
> Cc: Tom Lendacky <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
> ---
> arch/x86/kvm/svm/sev.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)

thanks

Reviewed-by: Brijesh Singh <[email protected]>


>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index a024edabaca5..02a66008e9b9 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -28,12 +28,17 @@
> #define __ex(x) __kvm_handle_fault_on_reboot(x)
>
> /* enable/disable SEV support */
> +#ifdef CONFIG_KVM_AMD_SEV
> static bool sev_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> module_param_named(sev, sev_enabled, bool, 0444);
>
> /* enable/disable SEV-ES support */
> static bool sev_es_enabled = IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT);
> module_param_named(sev_es, sev_es_enabled, bool, 0444);
> +#else
> +#define sev_enabled false
> +#define sev_es_enabled false
> +#endif /* CONFIG_KVM_AMD_SEV */
>
> static u8 sev_enc_bit;
> static int sev_flush_asids(void);
> @@ -1253,11 +1258,12 @@ void sev_vm_destroy(struct kvm *kvm)
>
> void __init sev_hardware_setup(void)
> {
> +#ifdef CONFIG_KVM_AMD_SEV
> unsigned int eax, ebx, ecx, edx;
> bool sev_es_supported = false;
> bool sev_supported = false;
>
> - if (!IS_ENABLED(CONFIG_KVM_AMD_SEV) || !sev_enabled)
> + if (!sev_enabled)
> goto out;
>
> /* Does the CPU support SEV? */
> @@ -1311,6 +1317,7 @@ void __init sev_hardware_setup(void)
> out:
> sev_enabled = sev_supported;
> sev_es_enabled = sev_es_supported;
> +#endif
> }
>
> void sev_hardware_teardown(void)