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SubjectRe: [RFC PATCH v5 027/104] KVM: TDX: initialize VM with TDX specific parameters
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On 3/4/22 20:48, isaku.yamahata@intel.com wrote:
> + td_params->attributes = init_vm->attributes;
> + if (td_params->attributes & TDX_TD_ATTRIBUTE_PERFMON) {
> + pr_warn("TD doesn't support perfmon. KVM needs to save/restore "
> + "host perf registers properly.\n");
> + return -EOPNOTSUPP;
> + }

Why does KVM have to hardcode this (and LBR/AMX below)? Is the level of
hardware support available from tdx_caps, for example through the CPUID
configs (0xA for this one, 0xD for LBR and AMX)?

> + /* PT can be exposed to TD guest regardless of KVM's XSS support */
> + guest_supported_xss &= (supported_xss | XFEATURE_MASK_PT);
> + td_params->xfam = guest_supported_xcr0 | guest_supported_xss;
> + if (td_params->xfam & TDX_TD_XFAM_LBR) {
> + pr_warn("TD doesn't support LBR. KVM needs to save/restore "
> + "IA32_LBR_DEPTH properly.\n");
> + return -EOPNOTSUPP;
> + }
> +
> + if (td_params->xfam & TDX_TD_XFAM_AMX) {
> + pr_warn("TD doesn't support AMX. KVM needs to save/restore "
> + "IA32_XFD, IA32_XFD_ERR properly.\n");
> + return -EOPNOTSUPP;
> + }

>
> + if (init_vm->tsc_khz)
> + guest_tsc_khz = init_vm->tsc_khz;
> + else
> + guest_tsc_khz = max_tsc_khz;

You can just use kvm->arch.default_tsc_khz in the latest kvm/queue.

> +#define BUILD_BUG_ON_MEMCPY(dst, src) \
> + do { \
> + BUILD_BUG_ON(sizeof(dst) != sizeof(src)); \
> + memcpy((dst), (src), sizeof(dst)); \
> + } while (0)
> +
> + BUILD_BUG_ON_MEMCPY(td_params->mrconfigid, init_vm->mrconfigid);
> + BUILD_BUG_ON_MEMCPY(td_params->mrowner, init_vm->mrowner);
> + BUILD_BUG_ON_MEMCPY(td_params->mrownerconfig, init_vm->mrownerconfig);
> +


Please rename to MEMCPY_SAME_SIZE.

Thanks,

Paolo

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