From: Joerg Roedel <joro@8bytes.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Joerg Roedel <jroedel@suse.de>
Subject: [PATCH 1/4] KVM: SVM: nested: Don't allocate VMCB structures on stack
Date: Wed, 29 Jul 2020 15:22:31 +0200 [thread overview]
Message-ID: <20200729132234.2346-2-joro@8bytes.org> (raw)
In-Reply-To: <20200729132234.2346-1-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
Do not allocate a vmcb_control_area and a vmcb_save_area on the stack,
as these structures will become larger with future extenstions of
SVM and thus the svm_set_nested_state() function will become a too large
stack frame.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kvm/svm/nested.c | 44 ++++++++++++++++++++++++++-------------
1 file changed, 30 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 61378a3c2ce4..f3c3c4e1ca7f 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1061,8 +1061,9 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
struct vmcb *hsave = svm->nested.hsave;
struct vmcb __user *user_vmcb = (struct vmcb __user *)
&user_kvm_nested_state->data.svm[0];
- struct vmcb_control_area ctl;
- struct vmcb_save_area save;
+ struct vmcb_control_area *ctl;
+ struct vmcb_save_area *save;
+ int ret;
u32 cr0;
if (kvm_state->format != KVM_STATE_NESTED_FORMAT_SVM)
@@ -1096,13 +1097,22 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
return -EINVAL;
if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE)
return -EINVAL;
- if (copy_from_user(&ctl, &user_vmcb->control, sizeof(ctl)))
- return -EFAULT;
- if (copy_from_user(&save, &user_vmcb->save, sizeof(save)))
- return -EFAULT;
- if (!nested_vmcb_check_controls(&ctl))
- return -EINVAL;
+ ret = -ENOMEM;
+ ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
+ save = kzalloc(sizeof(*save), GFP_KERNEL);
+ if (!ctl || !save)
+ goto out_free;
+
+ ret = -EFAULT;
+ if (copy_from_user(ctl, &user_vmcb->control, sizeof(ctl)))
+ goto out_free;
+ if (copy_from_user(save, &user_vmcb->save, sizeof(save)))
+ goto out_free;
+
+ ret = -EINVAL;
+ if (!nested_vmcb_check_controls(ctl))
+ goto out_free;
/*
* Processor state contains L2 state. Check that it is
@@ -1110,15 +1120,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
*/
cr0 = kvm_read_cr0(vcpu);
if (((cr0 & X86_CR0_CD) == 0) && (cr0 & X86_CR0_NW))
- return -EINVAL;
+ goto out_free;
/*
* Validate host state saved from before VMRUN (see
* nested_svm_check_permissions).
* TODO: validate reserved bits for all saved state.
*/
- if (!(save.cr0 & X86_CR0_PG))
- return -EINVAL;
+ if (!(save->cr0 & X86_CR0_PG))
+ goto out_free;
/*
* All checks done, we can enter guest mode. L1 control fields
@@ -1127,15 +1137,21 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
* contains saved L1 state.
*/
copy_vmcb_control_area(&hsave->control, &svm->vmcb->control);
- hsave->save = save;
+ hsave->save = *save;
svm->nested.vmcb = kvm_state->hdr.svm.vmcb_pa;
- load_nested_vmcb_control(svm, &ctl);
+ load_nested_vmcb_control(svm, ctl);
nested_prepare_vmcb_control(svm);
out_set_gif:
svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));
- return 0;
+
+ ret = 0;
+out_free:
+ kfree(save);
+ kfree(ctl);
+
+ return ret;
}
struct kvm_x86_nested_ops svm_nested_ops = {
--
2.17.1
next prev parent reply other threads:[~2020-07-29 13:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 13:22 [PATCH 0/4] KVM: SVM: SEV-ES groundwork Joerg Roedel
2020-07-29 13:22 ` Joerg Roedel [this message]
2020-07-29 15:14 ` [PATCH 1/4] KVM: SVM: nested: Don't allocate VMCB structures on stack Sean Christopherson
2020-07-30 12:38 ` Joerg Roedel
2020-07-29 13:22 ` [PATCH 2/4] KVM: SVM: Add GHCB definitions Joerg Roedel
2020-07-29 13:22 ` [PATCH 3/4] KVM: SVM: Add GHCB Accessor functions Joerg Roedel
2020-07-29 15:43 ` Sean Christopherson
2020-07-30 13:05 ` Joerg Roedel
2020-07-29 13:22 ` [PATCH 4/4] KVM: SVM: Use __packed shorthand Joerg Roedel
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