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Message-ID: <20200227181858.GA268538@vbusired-dt>
Date: Thu, 27 Feb 2020 12:18:58 -0600
From: Venu Busireddy <venu.busireddy@...cle.com>
To: Ashish Kalra <Ashish.Kalra@....com>
Cc: pbonzini@...hat.com, tglx@...utronix.de, mingo@...hat.com,
hpa@...or.com, rkrcmar@...hat.com, joro@...tes.org, bp@...e.de,
thomas.lendacky@....com, rientjes@...gle.com, x86@...nel.org,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/12] KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl
On 2020-02-27 11:57:50 -0600, Venu Busireddy wrote:
> On 2020-02-13 01:17:45 +0000, Ashish Kalra wrote:
> > From: Brijesh Singh <brijesh.singh@....com>
> >
> > The ioctl can be used to retrieve page encryption bitmap for a given
> > gfn range.
> >
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: Ingo Molnar <mingo@...hat.com>
> > Cc: "H. Peter Anvin" <hpa@...or.com>
> > Cc: Paolo Bonzini <pbonzini@...hat.com>
> > Cc: "Radim Krčmář" <rkrcmar@...hat.com>
> > Cc: Joerg Roedel <joro@...tes.org>
> > Cc: Borislav Petkov <bp@...e.de>
> > Cc: Tom Lendacky <thomas.lendacky@....com>
> > Cc: x86@...nel.org
> > Cc: kvm@...r.kernel.org
> > Cc: linux-kernel@...r.kernel.org
> > Signed-off-by: Brijesh Singh <brijesh.singh@....com>
> > Signed-off-by: Ashish Kalra <ashish.kalra@....com>
>
> This patch does not apply to upstream Linux version 5.5.6.
>
> <snip>
> Applying: KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl
> error: patch failed: Documentation/virt/kvm/api.txt:4213
> error: Documentation/virt/kvm/api.txt: patch does not apply
> error: patch failed: include/uapi/linux/kvm.h:1478
> error: include/uapi/linux/kvm.h: patch does not apply
> Patch failed at 0009 KVM: x86: Introduce KVM_GET_PAGE_ENC_BITMAP ioctl
> <snip>
>
> Which kernel version does this patch series apply to, cleanly?
Tried git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git.
With that, patch 08/12 fails with the top of that tree, as well as
tag v5.6-rc3.
> Thanks,
>
> Venu
>
> > ---
> > Documentation/virt/kvm/api.txt | 27 +++++++++++++++++++++
> > arch/x86/include/asm/kvm_host.h | 2 ++
> > arch/x86/kvm/svm.c | 43 +++++++++++++++++++++++++++++++++
> > arch/x86/kvm/x86.c | 12 +++++++++
> > include/uapi/linux/kvm.h | 12 +++++++++
> > 5 files changed, 96 insertions(+)
> >
> > diff --git a/Documentation/virt/kvm/api.txt b/Documentation/virt/kvm/api.txt
> > index c6e1ce5d40de..053aecfabe74 100644
> > --- a/Documentation/virt/kvm/api.txt
> > +++ b/Documentation/virt/kvm/api.txt
> > @@ -4213,6 +4213,33 @@ the clear cpu reset definition in the POP. However, the cpu is not put
> > into ESA mode. This reset is a superset of the initial reset.
> >
> >
> > +4.120 KVM_GET_PAGE_ENC_BITMAP (vm ioctl)
> > +
> > +Capability: basic
> > +Architectures: x86
> > +Type: vm ioctl
> > +Parameters: struct kvm_page_enc_bitmap (in/out)
> > +Returns: 0 on success, -1 on error
> > +
> > +/* for KVM_GET_PAGE_ENC_BITMAP */
> > +struct kvm_page_enc_bitmap {
> > + __u64 start_gfn;
> > + __u64 num_pages;
> > + union {
> > + void __user *enc_bitmap; /* one bit per page */
> > + __u64 padding2;
> > + };
> > +};
> > +
> > +The encrypted VMs have concept of private and shared pages. The private
> > +page is encrypted with the guest-specific key, while shared page may
> > +be encrypted with the hypervisor key. The KVM_GET_PAGE_ENC_BITMAP can
> > +be used to get the bitmap indicating whether the guest page is private
> > +or shared. The bitmap can be used during the guest migration, if the page
> > +is private then userspace need to use SEV migration commands to transmit
> > +the page.
> > +
> > +
> > 5. The kvm_run structure
> > ------------------------
> >
> > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > index 4ae7293033b2..a6882c5214b4 100644
> > --- a/arch/x86/include/asm/kvm_host.h
> > +++ b/arch/x86/include/asm/kvm_host.h
> > @@ -1258,6 +1258,8 @@ struct kvm_x86_ops {
> > int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
> > int (*page_enc_status_hc)(struct kvm *kvm, unsigned long gpa,
> > unsigned long sz, unsigned long mode);
> > + int (*get_page_enc_bitmap)(struct kvm *kvm,
> > + struct kvm_page_enc_bitmap *bmap);
> > };
> >
> > struct kvm_arch_async_pf {
> > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> > index f09791109075..f1c8806a97c6 100644
> > --- a/arch/x86/kvm/svm.c
> > +++ b/arch/x86/kvm/svm.c
> > @@ -7673,6 +7673,48 @@ static int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa,
> > return ret;
> > }
> >
> > +static int svm_get_page_enc_bitmap(struct kvm *kvm,
> > + struct kvm_page_enc_bitmap *bmap)
> > +{
> > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > + unsigned long gfn_start, gfn_end;
> > + unsigned long *bitmap;
> > + unsigned long sz, i;
> > + int ret;
> > +
> > + if (!sev_guest(kvm))
> > + return -ENOTTY;
> > +
> > + gfn_start = bmap->start_gfn;
> > + gfn_end = gfn_start + bmap->num_pages;
> > +
> > + sz = ALIGN(bmap->num_pages, BITS_PER_LONG) / 8;
> > + bitmap = kmalloc(sz, GFP_KERNEL);
> > + if (!bitmap)
> > + return -ENOMEM;
> > +
> > + /* by default all pages are marked encrypted */
> > + memset(bitmap, 0xff, sz);
> > +
> > + mutex_lock(&kvm->lock);
> > + if (sev->page_enc_bmap) {
> > + i = gfn_start;
> > + for_each_clear_bit_from(i, sev->page_enc_bmap,
> > + min(sev->page_enc_bmap_size, gfn_end))
> > + clear_bit(i - gfn_start, bitmap);
> > + }
> > + mutex_unlock(&kvm->lock);
> > +
> > + ret = -EFAULT;
> > + if (copy_to_user(bmap->enc_bitmap, bitmap, sz))
> > + goto out;
> > +
> > + ret = 0;
> > +out:
> > + kfree(bitmap);
> > + return ret;
> > +}
> > +
> > static int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
> > {
> > struct kvm_sev_cmd sev_cmd;
> > @@ -8066,6 +8108,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
> > .apic_init_signal_blocked = svm_apic_init_signal_blocked,
> >
> > .page_enc_status_hc = svm_page_enc_status_hc,
> > + .get_page_enc_bitmap = svm_get_page_enc_bitmap,
> > };
> >
> > static int __init svm_init(void)
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 298627fa3d39..e955f886ee17 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -5213,6 +5213,18 @@ long kvm_arch_vm_ioctl(struct file *filp,
> > case KVM_SET_PMU_EVENT_FILTER:
> > r = kvm_vm_ioctl_set_pmu_event_filter(kvm, argp);
> > break;
> > + case KVM_GET_PAGE_ENC_BITMAP: {
> > + struct kvm_page_enc_bitmap bitmap;
> > +
> > + r = -EFAULT;
> > + if (copy_from_user(&bitmap, argp, sizeof(bitmap)))
> > + goto out;
> > +
> > + r = -ENOTTY;
> > + if (kvm_x86_ops->get_page_enc_bitmap)
> > + r = kvm_x86_ops->get_page_enc_bitmap(kvm, &bitmap);
> > + break;
> > + }
> > default:
> > r = -ENOTTY;
> > }
> > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> > index 4e80c57a3182..9377b26c5f4e 100644
> > --- a/include/uapi/linux/kvm.h
> > +++ b/include/uapi/linux/kvm.h
> > @@ -500,6 +500,16 @@ struct kvm_dirty_log {
> > };
> > };
> >
> > +/* for KVM_GET_PAGE_ENC_BITMAP */
> > +struct kvm_page_enc_bitmap {
> > + __u64 start_gfn;
> > + __u64 num_pages;
> > + union {
> > + void __user *enc_bitmap; /* one bit per page */
> > + __u64 padding2;
> > + };
> > +};
> > +
> > /* for KVM_CLEAR_DIRTY_LOG */
> > struct kvm_clear_dirty_log {
> > __u32 slot;
> > @@ -1478,6 +1488,8 @@ struct kvm_enc_region {
> > #define KVM_S390_NORMAL_RESET _IO(KVMIO, 0xc3)
> > #define KVM_S390_CLEAR_RESET _IO(KVMIO, 0xc4)
> >
> > +#define KVM_GET_PAGE_ENC_BITMAP _IOW(KVMIO, 0xc2, struct kvm_page_enc_bitmap)
> > +
> > /* Secure Encrypted Virtualization command */
> > enum sev_cmd_id {
> > /* Guest initialization commands */
> > --
> > 2.17.1
> >
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