lkml.org 
[lkml]   [2020]   [Apr]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v6 12/14] KVM: x86: Introduce KVM_PAGE_ENC_BITMAP_RESET ioctl
From
Date

On 4/3/20 2:45 PM, Ashish Kalra wrote:
> On Fri, Apr 03, 2020 at 02:14:23PM -0700, Krish Sadhukhan wrote:
>> On 3/29/20 11:23 PM, Ashish Kalra wrote:
>>> From: Ashish Kalra <ashish.kalra@amd.com>
>>>
>>> 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@amd.com>
>>> ---
>>> 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,
>>
>> We don't need to initialize the intel ops to NULL ? It's not initialized in
>> the previous patch either.
>>
>>> };
> This struct is declared as "static storage", so won't the non-initialized
> members be 0 ?


Correct. Although, I see that 'nested_enable_evmcs' is explicitly
initialized. We should maintain the convention, perhaps.

>
>>> 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 {
>> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>

\
 
 \ /
  Last update: 2020-04-06 20:54    [W:0.081 / U:2.944 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site