Let's print available ASID ranges for SEV/SEV-ES guests.
This information can be useful for system administrator
to debug if SEV/SEV-ES fails to enable.
There are a few reasons.
SEV:
- NPT is disabled (module parameter)
- CPU lacks some features (sev, decodeassists)
- Maximum SEV ASID is 0
SEV-ES:
- mmio_caching is disabled (module parameter)
- CPU lacks sev_es feature
- Minimum SEV ASID value is 1 (can be adjusted in BIOS/UEFI)
Cc: Sean Christopherson <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Stéphane Graber <[email protected]>
Cc: [email protected]
Cc: [email protected]
Suggested-by: Sean Christopherson <[email protected]>
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
---
v2:
- print only the ASID ranges according to Sean's suggestion
---
arch/x86/kvm/svm/sev.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index cc832a8d1bca..fff63d1f2a34 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2224,7 +2224,6 @@ void __init sev_hardware_setup(void)
goto out;
}
- pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
sev_supported = true;
/* SEV-ES support requested? */
@@ -2252,10 +2251,16 @@ void __init sev_hardware_setup(void)
if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
goto out;
- pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
sev_es_supported = true;
out:
+ if (boot_cpu_has(X86_FEATURE_SEV))
+ pr_info("SEV %s (ASIDs %u - %u)\n",
+ sev_supported ? "enabled" : "disabled", min_sev_asid, max_sev_asid);
+ if (boot_cpu_has(X86_FEATURE_SEV_ES))
+ pr_info("SEV-ES %s (ASIDs %u - %u)\n",
+ sev_es_supported ? "enabled" : "disabled", 1, min_sev_asid - 1);
+
sev_enabled = sev_supported;
sev_es_enabled = sev_es_supported;
#endif
--
2.34.1
On Mon, May 22, 2023, Alexander Mikhalitsyn wrote:
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index cc832a8d1bca..fff63d1f2a34 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -2224,7 +2224,6 @@ void __init sev_hardware_setup(void)
> goto out;
> }
>
> - pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
> sev_supported = true;
>
> /* SEV-ES support requested? */
> @@ -2252,10 +2251,16 @@ void __init sev_hardware_setup(void)
> if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
> goto out;
>
> - pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
> sev_es_supported = true;
>
> out:
> + if (boot_cpu_has(X86_FEATURE_SEV))
> + pr_info("SEV %s (ASIDs %u - %u)\n",
> + sev_supported ? "enabled" : "disabled", min_sev_asid, max_sev_asid);
> + if (boot_cpu_has(X86_FEATURE_SEV_ES))
> + pr_info("SEV-ES %s (ASIDs %u - %u)\n",
> + sev_es_supported ? "enabled" : "disabled", 1, min_sev_asid - 1);
The min should print '0' if min_sev_asid<=1, otherwise the output will be
SEV-ES disabled (ASIDs 1 - 0)
which is confusing. That would also align with what gets printed out for SEV
when it's not supported at all (min==max=0).
No need for v3, I'll fixup when applying.
On Tue, Jun 6, 2023 at 8:46 PM Sean Christopherson <[email protected]> wrote:
>
> On Mon, May 22, 2023, Alexander Mikhalitsyn wrote:
> > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> > index cc832a8d1bca..fff63d1f2a34 100644
> > --- a/arch/x86/kvm/svm/sev.c
> > +++ b/arch/x86/kvm/svm/sev.c
> > @@ -2224,7 +2224,6 @@ void __init sev_hardware_setup(void)
> > goto out;
> > }
> >
> > - pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
> > sev_supported = true;
> >
> > /* SEV-ES support requested? */
> > @@ -2252,10 +2251,16 @@ void __init sev_hardware_setup(void)
> > if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
> > goto out;
> >
> > - pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
> > sev_es_supported = true;
> >
> > out:
> > + if (boot_cpu_has(X86_FEATURE_SEV))
> > + pr_info("SEV %s (ASIDs %u - %u)\n",
> > + sev_supported ? "enabled" : "disabled", min_sev_asid, max_sev_asid);
> > + if (boot_cpu_has(X86_FEATURE_SEV_ES))
> > + pr_info("SEV-ES %s (ASIDs %u - %u)\n",
> > + sev_es_supported ? "enabled" : "disabled", 1, min_sev_asid - 1);
>
> The min should print '0' if min_sev_asid<=1, otherwise the output will be
>
> SEV-ES disabled (ASIDs 1 - 0)
>
> which is confusing. That would also align with what gets printed out for SEV
> when it's not supported at all (min==max=0).
>
> No need for v3, I'll fixup when applying.
Got it. Ok!
Thanks again for looking into that.
Kind regards,
Alex