On 2020-03-30 06:23:10 +0000, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@xxxxxxx>
>
> This ioctl can be used by the application to reset the page
> encryption bitmap managed by the KVM driver. A typical usage
> for this ioctl is on VM reboot, on reboot, we must reinitialize
> the bitmap.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
Reviewed-by: Venu Busireddy <venu.busireddy@xxxxxxxxxx>
> ---
> Documentation/virt/kvm/api.rst | 13 +++++++++++++
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/svm.c | 16 ++++++++++++++++
> arch/x86/kvm/x86.c | 6 ++++++
> include/uapi/linux/kvm.h | 1 +
> 5 files changed, 37 insertions(+)
>
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index 4d1004a154f6..a11326ccc51d 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -4698,6 +4698,19 @@ During the guest live migration the outgoing guest exports its page encryption
> bitmap, the KVM_SET_PAGE_ENC_BITMAP can be used to build the page encryption
> bitmap for an incoming guest.
>
> +4.127 KVM_PAGE_ENC_BITMAP_RESET (vm ioctl)
> +-----------------------------------------
> +
> +:Capability: basic
> +:Architectures: x86
> +:Type: vm ioctl
> +:Parameters: none
> +:Returns: 0 on success, -1 on error
> +
> +The KVM_PAGE_ENC_BITMAP_RESET is used to reset the guest's page encryption
> +bitmap during guest reboot and this is only done on the guest's boot vCPU.
> +
> +
> 5. The kvm_run structure
> ========================
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index d30f770aaaea..a96ef6338cd2 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1273,6 +1273,7 @@ struct kvm_x86_ops {
> struct kvm_page_enc_bitmap *bmap);
> int (*set_page_enc_bitmap)(struct kvm *kvm,
> struct kvm_page_enc_bitmap *bmap);
> + int (*reset_page_enc_bitmap)(struct kvm *kvm);
> };
>
> struct kvm_arch_async_pf {
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 313343a43045..c99b0207a443 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -7797,6 +7797,21 @@ static int svm_set_page_enc_bitmap(struct kvm *kvm,
> return ret;
> }
>
> +static int svm_reset_page_enc_bitmap(struct kvm *kvm)
> +{
> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> +
> + if (!sev_guest(kvm))
> + return -ENOTTY;
> +
> + mutex_lock(&kvm->lock);
> + /* by default all pages should be marked encrypted */
> + if (sev->page_enc_bmap_size)
> + bitmap_fill(sev->page_enc_bmap, sev->page_enc_bmap_size);
> + mutex_unlock(&kvm->lock);
> + return 0;
> +}
> +
> static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> {
> struct kvm_sev_cmd sev_cmd;
> @@ -8203,6 +8218,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
> .page_enc_status_hc = svm_page_enc_status_hc,
> .get_page_enc_bitmap = svm_get_page_enc_bitmap,
> .set_page_enc_bitmap = svm_set_page_enc_bitmap,
> + .reset_page_enc_bitmap = svm_reset_page_enc_bitmap,
> };
>
> static int __init svm_init(void)
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 05e953b2ec61..2127ed937f53 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5250,6 +5250,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
> r = kvm_x86_ops->set_page_enc_bitmap(kvm, &bitmap);
> break;
> }
> + case KVM_PAGE_ENC_BITMAP_RESET: {
> + r = -ENOTTY;
> + if (kvm_x86_ops->reset_page_enc_bitmap)
> + r = kvm_x86_ops->reset_page_enc_bitmap(kvm);
> + break;
> + }
> default:
> r = -ENOTTY;
> }
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index b4b01d47e568..0884a581fc37 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1490,6 +1490,7 @@ struct kvm_enc_region {
>
> #define KVM_GET_PAGE_ENC_BITMAP _IOW(KVMIO, 0xc5, struct kvm_page_enc_bitmap)
> #define KVM_SET_PAGE_ENC_BITMAP _IOW(KVMIO, 0xc6, struct kvm_page_enc_bitmap)
> +#define KVM_PAGE_ENC_BITMAP_RESET _IO(KVMIO, 0xc7)
>
> /* Secure Encrypted Virtualization command */
> enum sev_cmd_id {
> --
> 2.17.1
>
