[libvirt PATCH v3 10/13] qemu: report max number of SEV guests

[Peter Krempa]

On Fri, Dec 10, 2021 at 16:47:10 +0000, Daniel P. Berrangé wrote:
> Different CPU generations have different limits on the number
> of SEV/SEV-ES guests that can be run. Since both limits come
> from the same overall set, there is typically also BIOS config
> to set the tradeoff betweeen SEV and SEV-ES guest limits.
> 
> This is important information to expose for a mgmt application
> scheduling guests to hosts.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  src/qemu/qemu_capabilities.c                  | 39 +++++++++++++++++++
>  src/qemu/qemu_driver.c                        | 10 +++++
>  .../domaincapsdata/qemu_2.12.0-q35.x86_64.xml |  4 +-
>  .../domaincapsdata/qemu_2.12.0-tcg.x86_64.xml |  4 +-
>  tests/domaincapsdata/qemu_2.12.0.x86_64.xml   |  4 +-
>  .../domaincapsdata/qemu_6.0.0-q35.x86_64.xml  |  4 +-
>  .../domaincapsdata/qemu_6.0.0-tcg.x86_64.xml  |  4 +-
>  tests/domaincapsdata/qemu_6.0.0.x86_64.xml    |  4 +-
>  tests/testutilsqemu.c                         | 21 ++++++++++
>  9 files changed, 82 insertions(+), 12 deletions(-)

[...]

> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index ee23e10543..8ee0939295 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -19918,6 +19918,16 @@ qemuGetSEVInfoToParams(virQEMUCaps *qemuCaps,
>                      sev->reduced_phys_bits) < 0)
>          goto cleanup;
>  
> +    if (virTypedParamsAddUInt(&sevParams, &n, &maxpar,
> +                    VIR_NODE_SEV_MAX_GUESTS,
> +                    sev->max_guests) < 0)
> +        goto cleanup;
> +
> +    if (virTypedParamsAddUInt(&sevParams, &n, &maxpar,
> +                    VIR_NODE_SEV_MAX_ES_GUESTS,
> +                    sev->max_es_guests) < 0)
> +        goto cleanup;

Both calls have broken alignment.


[...]

> diff --git a/tests/testutilsqemu.c b/tests/testutilsqemu.c
> index 5bd1d40ad4..7f848f158e 100644
> --- a/tests/testutilsqemu.c
> +++ b/tests/testutilsqemu.c
> @@ -143,6 +143,27 @@ virCapabilitiesHostNUMANewHost(void)
>      return virTestCapsBuildNUMATopology(3);
>  }
>  
> +void

This form of overriding functions looked a bit unorthodox but prior art
is right above, so it's okay.

> +virHostCPUX86GetCPUID(uint32_t leaf,
> +                      uint32_t extended,
> +                      uint32_t *eax,
> +                      uint32_t *ebx,
> +                      uint32_t *ecx,
> +                      uint32_t *edx)
> +{
> +    if (eax)
> +        *eax = 0;
> +    if (ebx)
> +        *ebx = 0;
> +    if (ecx)
> +        *ecx = 0;
> +    if (edx)
> +        *edx = 0;
> +    if (leaf == 0x8000001F && extended == 0) {
> +        *ecx = 509;
> +        *edx = 451;

ecx/edx are unconditionally dereferenced here. Okay at this point but
possibly unextensible. Consider adding pointer checks at least to avoid
coverity moaning.

Reviewed-by: Peter Krempa <pkrempa at redhat.com>