Messages in this thread | | | Subject | Re: [PATCH v6 12/14] KVM: x86: Introduce KVM_PAGE_ENC_BITMAP_RESET ioctl | From | Krish Sadhukhan <> | Date | Mon, 6 Apr 2020 11:52:59 -0700 |
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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>
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