RE: [PATCH V2 9/9] x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES

[Michael Kelley (LINUX)]

From: Tianyu Lan <ltykernel@xxxxxxxxx> Sent: Monday, June 26, 2023 8:23 PM
> 
> Add Hyperv-specific handling for faults caused by VMMCALL
> instructions.
> 
> Signed-off-by: Tianyu Lan <tiala@xxxxxxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/mshyperv.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 8e1d9ed6a1e0..ba9a3a65f664 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -32,6 +32,7 @@
>  #include <asm/nmi.h>
>  #include <clocksource/hyperv_timer.h>
>  #include <asm/numa.h>
> +#include <asm/svm.h>
> 
>  /* Is Linux running as the root partition? */
>  bool hv_root_partition;
> @@ -577,6 +578,20 @@ static bool __init ms_hyperv_msi_ext_dest_id(void)
>  	return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;
>  }
> 
> +static void hv_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
> +{
> +	/* RAX and CPL are already in the GHCB */
> +	ghcb_set_rcx(ghcb, regs->cx);
> +	ghcb_set_rdx(ghcb, regs->dx);
> +	ghcb_set_r8(ghcb, regs->r8);
> +}
> +
> +static bool hv_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
> +{
> +	/* No checking of the return state needed */
> +	return true;
> +}
> +
>  const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
>  	.name			= "Microsoft Hyper-V",
>  	.detect			= ms_hyperv_platform,
> @@ -584,4 +599,6 @@ const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv
> = {
>  	.init.x2apic_available	= ms_hyperv_x2apic_available,
>  	.init.msi_ext_dest_id	= ms_hyperv_msi_ext_dest_id,
>  	.init.init_platform	= ms_hyperv_init_platform,
> +	.runtime.sev_es_hcall_prepare = hv_sev_es_hcall_prepare,
> +	.runtime.sev_es_hcall_finish = hv_sev_es_hcall_finish,
>  };
> --
> 2.25.1

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>