* [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter
@ 2019-12-15 2:11 Sukadev Bhattiprolu
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
2019-12-18 5:32 ` [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Paul Mackerras
0 siblings, 2 replies; 10+ messages in thread
From: Sukadev Bhattiprolu @ 2019-12-15 2:11 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxram, kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
This patch is based on Bharata's v11 KVM patches for secure guests:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-November/200918.html
---
From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Date: Fri, 13 Dec 2019 15:06:16 -0600
Subject: [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter
Add 'skip_page_out' parameter to kvmppc_uvmem_drop_pages() which will
be needed in a follow-on patch that implements H_SVM_INIT_ABORT hcall.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
arch/powerpc/include/asm/kvm_book3s_uvmem.h | 4 ++--
arch/powerpc/kvm/book3s_64_mmu_radix.c | 2 +-
arch/powerpc/kvm/book3s_hv.c | 2 +-
arch/powerpc/kvm/book3s_hv_uvmem.c | 4 ++--
4 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
index 50204e228f16..3cf8425b9838 100644
--- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
+++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
@@ -20,7 +20,7 @@ unsigned long kvmppc_h_svm_init_start(struct kvm *kvm);
unsigned long kvmppc_h_svm_init_done(struct kvm *kvm);
int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn);
void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
- struct kvm *kvm);
+ struct kvm *kvm, bool skip_page_out);
#else
static inline int kvmppc_uvmem_init(void)
{
@@ -69,6 +69,6 @@ static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
static inline void
kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
- struct kvm *kvm) { }
+ struct kvm *kvm, bool skip_page_out) { }
#endif /* CONFIG_PPC_UV */
#endif /* __ASM_KVM_BOOK3S_UVMEM_H__ */
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index da857c8ba6e4..744dba98e5d1 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -1102,7 +1102,7 @@ void kvmppc_radix_flush_memslot(struct kvm *kvm,
unsigned int shift;
if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START)
- kvmppc_uvmem_drop_pages(memslot, kvm);
+ kvmppc_uvmem_drop_pages(memslot, kvm, true);
if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
return;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 597f4bfecf0e..66d5312be16b 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5493,7 +5493,7 @@ static int kvmhv_svm_off(struct kvm *kvm)
continue;
kvm_for_each_memslot(memslot, slots) {
- kvmppc_uvmem_drop_pages(memslot, kvm);
+ kvmppc_uvmem_drop_pages(memslot, kvm, true);
uv_unregister_mem_slot(kvm->arch.lpid, memslot->id);
}
}
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index f24ac3cfb34c..9a5bbad7d87e 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -259,7 +259,7 @@ unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
* QEMU page table with normal PTEs from newly allocated pages.
*/
void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
- struct kvm *kvm)
+ struct kvm *kvm, bool skip_page_out)
{
int i;
struct kvmppc_uvmem_page_pvt *pvt;
@@ -277,7 +277,7 @@ void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
uvmem_page = pfn_to_page(uvmem_pfn);
pvt = uvmem_page->zone_device_data;
- pvt->skip_page_out = true;
+ pvt->skip_page_out = skip_page_out;
mutex_unlock(&kvm->arch.uvmem_lock);
pfn = gfn_to_pfn(kvm, gfn);
--
2.17.2
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-15 2:11 [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Sukadev Bhattiprolu
@ 2019-12-15 2:12 ` Sukadev Bhattiprolu
2019-12-16 3:29 ` Bharata B Rao
` (2 more replies)
2019-12-18 5:32 ` [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Paul Mackerras
1 sibling, 3 replies; 10+ messages in thread
From: Sukadev Bhattiprolu @ 2019-12-15 2:12 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxram, kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
Implement the H_SVM_INIT_ABORT hcall which the Ultravisor can use to
abort an SVM after it has issued the H_SVM_INIT_START and before the
H_SVM_INIT_DONE hcalls. This hcall could be used when Ultravisor
encounters security violations or other errors when starting an SVM.
Note that this hcall is different from UV_SVM_TERMINATE ucall which
is used by HV to terminate/cleanup an VM that has becore secure.
The H_SVM_INIT_ABORT should basically undo operations that were done
since the H_SVM_INIT_START hcall - i.e page-out all the VM pages back
to normal memory, and terminate the SVM.
(If we do not bring the pages back to normal memory, the text/data
of the VM would be stuck in secure memory and since the SVM did not
go secure, its MSR_S bit will be clear and the VM wont be able to
access its pages even to do a clean exit).
Based on patches and discussion with Paul Mackerras, Ram Pai and
Bharata Rao.
Signed-off-by: Ram Pai <linuxram@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
---
Changelog[v3]:
- Rather than pass the NIP/MSR as parameters, load them into
SRR0/SRR1 (like we do with other registers) and terminate
the VM after paging out pages
- Move the code to add a skip_page_out parameter into a
separate patch.
Changelog[v2]:
[Paul Mackerras] avoid returning to UV "one last time" after
the state is cleaned up. So, we now have H_SVM_INIT_ABORT:
- take the VM's NIP/MSR register states as parameters
- inherit the state of other registers as at UV_ESM call.
After cleaning up the partial state, HV uses these to return
directly to the VM with a failed UV_ESM call.
---
Documentation/powerpc/ultravisor.rst | 57 +++++++++++++++++++++
arch/powerpc/include/asm/hvcall.h | 1 +
arch/powerpc/include/asm/kvm_book3s_uvmem.h | 6 +++
arch/powerpc/include/asm/kvm_host.h | 1 +
arch/powerpc/kvm/book3s_hv.c | 3 ++
arch/powerpc/kvm/book3s_hv_uvmem.c | 24 +++++++++
6 files changed, 92 insertions(+)
diff --git a/Documentation/powerpc/ultravisor.rst b/Documentation/powerpc/ultravisor.rst
index 730854f73830..8c114c071bfa 100644
--- a/Documentation/powerpc/ultravisor.rst
+++ b/Documentation/powerpc/ultravisor.rst
@@ -948,6 +948,63 @@ Use cases
up its internal state for this virtual machine.
+H_SVM_INIT_ABORT
+----------------
+
+ Abort the process of securing an SVM.
+
+Syntax
+~~~~~~
+
+.. code-block:: c
+
+ uint64_t hypercall(const uint64_t H_SVM_INIT_ABORT)
+
+Return values
+~~~~~~~~~~~~~
+
+ One of the following values:
+
+ * H_PARAMETER on successfully cleaning up the state,
+ Hypervisor will return this value to the
+ **guest**, to indicate that the underlying
+ UV_ESM ultracall failed.
+
+ * H_UNSUPPORTED if called from the wrong context (e.g. from
+ an SVM or before an H_SVM_INIT_START hypercall).
+
+Description
+~~~~~~~~~~~
+
+ Abort the process of securing a virtual machine. This call must
+ be made after a prior call to ``H_SVM_INIT_START`` hypercall and
+ before a call to ``H_SVM_INIT_DONE``.
+
+ On entry into this hypercall the non-volatile GPRs and FPRs are
+ expected to contain the values they had at the time the VM issued
+ the UV_ESM ultracall. Further ``SRR0`` is expected to contain the
+ address of the instruction after the ``UV_ESM`` ultracall and ``SRR1``
+ the MSR value with which to return to the VM.
+
+ This hypercall will cleanup any partial state that was established for
+ the VM since the prior ``H_SVM_INIT_START`` hypercall, including paging
+ out pages that were paged-into secure memory, and issue the
+ ``UV_SVM_TERMINATE`` ultracall to terminate the VM.
+
+ After the partial state is cleaned up, control returns to the VM
+ (**not Ultravisor**), at the address specified in ``SRR0`` with the
+ MSR values set to the value in ``SRR1``.
+
+Use cases
+~~~~~~~~~
+
+ If after a successful call to ``H_SVM_INIT_START``, the Ultravisor
+ encounters an error while securing a virtual machine, either due
+ to lack of resources or because the VM's security information could
+ not be validated, Ultravisor informs the Hypervisor about it.
+ Hypervisor should use this call to clean up any internal state for
+ this virtual machine and return to the VM.
+
H_SVM_PAGE_IN
-------------
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 13bd870609c3..e90c073e437e 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -350,6 +350,7 @@
#define H_SVM_PAGE_OUT 0xEF04
#define H_SVM_INIT_START 0xEF08
#define H_SVM_INIT_DONE 0xEF0C
+#define H_SVM_INIT_ABORT 0xEF14
/* Values for 2nd argument to H_SET_MODE */
#define H_SET_MODE_RESOURCE_SET_CIABR 1
diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
index 3cf8425b9838..5a9834e0e2d1 100644
--- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
+++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
@@ -19,6 +19,7 @@ unsigned long kvmppc_h_svm_page_out(struct kvm *kvm,
unsigned long kvmppc_h_svm_init_start(struct kvm *kvm);
unsigned long kvmppc_h_svm_init_done(struct kvm *kvm);
int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn);
+unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm);
void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
struct kvm *kvm, bool skip_page_out);
#else
@@ -62,6 +63,11 @@ static inline unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
return H_UNSUPPORTED;
}
+static inline unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
+{
+ return H_UNSUPPORTED;
+}
+
static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
{
return -EFAULT;
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 577ca95fac7c..8310c0407383 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -278,6 +278,7 @@ struct kvm_resize_hpt;
/* Flag values for kvm_arch.secure_guest */
#define KVMPPC_SECURE_INIT_START 0x1 /* H_SVM_INIT_START has been called */
#define KVMPPC_SECURE_INIT_DONE 0x2 /* H_SVM_INIT_DONE completed */
+#define KVMPPC_SECURE_INIT_ABORT 0x4 /* H_SVM_INIT_ABORT issued */
struct kvm_arch {
unsigned int lpid;
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 66d5312be16b..1b22f2c7ad1b 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1099,6 +1099,9 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
case H_SVM_INIT_DONE:
ret = kvmppc_h_svm_init_done(vcpu->kvm);
break;
+ case H_SVM_INIT_ABORT:
+ ret = kvmppc_h_svm_init_abort(vcpu->kvm);
+ break;
default:
return RESUME_HOST;
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 9a5bbad7d87e..f7df8c327468 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -287,6 +287,30 @@ void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
}
}
+unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
+{
+ int i;
+
+ if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
+ return H_UNSUPPORTED;
+
+ for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ struct kvm_memory_slot *memslot;
+ struct kvm_memslots *slots = __kvm_memslots(kvm, i);
+
+ if (!slots)
+ continue;
+
+ kvm_for_each_memslot(memslot, slots)
+ kvmppc_uvmem_drop_pages(memslot, kvm, false);
+ }
+
+ kvm->arch.secure_guest = 0;
+ uv_svm_terminate(kvm->arch.lpid);
+
+ return H_PARAMETER;
+}
+
/*
* Get a free device PFN from the pool
*
--
2.17.2
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
@ 2019-12-16 3:29 ` Bharata B Rao
2019-12-19 21:50 ` Sukadev Bhattiprolu
2019-12-18 5:36 ` Paul Mackerras
2020-01-03 0:18 ` Ram Pai
2 siblings, 1 reply; 10+ messages in thread
From: Bharata B Rao @ 2019-12-16 3:29 UTC (permalink / raw)
To: Sukadev Bhattiprolu; +Cc: linuxram, kvm-ppc, linux-mm, linuxppc-dev
On Sat, Dec 14, 2019 at 06:12:08PM -0800, Sukadev Bhattiprolu wrote:
> +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> +{
> + int i;
> +
> + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
> + return H_UNSUPPORTED;
> +
> + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
> + struct kvm_memory_slot *memslot;
> + struct kvm_memslots *slots = __kvm_memslots(kvm, i);
> +
> + if (!slots)
> + continue;
> +
> + kvm_for_each_memslot(memslot, slots)
> + kvmppc_uvmem_drop_pages(memslot, kvm, false);
> + }
You need to hold srcu_read_lock(&kvm->srcu) here.
Regards,
Bharata.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter
2019-12-15 2:11 [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Sukadev Bhattiprolu
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
@ 2019-12-18 5:32 ` Paul Mackerras
1 sibling, 0 replies; 10+ messages in thread
From: Paul Mackerras @ 2019-12-18 5:32 UTC (permalink / raw)
To: Sukadev Bhattiprolu
Cc: linuxram, kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
On Sat, Dec 14, 2019 at 06:11:04PM -0800, Sukadev Bhattiprolu wrote:
>
> This patch is based on Bharata's v11 KVM patches for secure guests:
> https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-November/200918.html
> ---
>
> From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> Date: Fri, 13 Dec 2019 15:06:16 -0600
> Subject: [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter
>
> Add 'skip_page_out' parameter to kvmppc_uvmem_drop_pages() which will
> be needed in a follow-on patch that implements H_SVM_INIT_ABORT hcall.
>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
2019-12-16 3:29 ` Bharata B Rao
@ 2019-12-18 5:36 ` Paul Mackerras
2019-12-19 21:51 ` Sukadev Bhattiprolu
2020-01-03 0:18 ` Ram Pai
2 siblings, 1 reply; 10+ messages in thread
From: Paul Mackerras @ 2019-12-18 5:36 UTC (permalink / raw)
To: Sukadev Bhattiprolu
Cc: linuxram, kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
On Sat, Dec 14, 2019 at 06:12:08PM -0800, Sukadev Bhattiprolu wrote:
>
> Implement the H_SVM_INIT_ABORT hcall which the Ultravisor can use to
> abort an SVM after it has issued the H_SVM_INIT_START and before the
> H_SVM_INIT_DONE hcalls. This hcall could be used when Ultravisor
> encounters security violations or other errors when starting an SVM.
>
> Note that this hcall is different from UV_SVM_TERMINATE ucall which
> is used by HV to terminate/cleanup an VM that has becore secure.
>
> The H_SVM_INIT_ABORT should basically undo operations that were done
> since the H_SVM_INIT_START hcall - i.e page-out all the VM pages back
> to normal memory, and terminate the SVM.
>
> (If we do not bring the pages back to normal memory, the text/data
> of the VM would be stuck in secure memory and since the SVM did not
> go secure, its MSR_S bit will be clear and the VM wont be able to
> access its pages even to do a clean exit).
>
> Based on patches and discussion with Paul Mackerras, Ram Pai and
> Bharata Rao.
>
> Signed-off-by: Ram Pai <linuxram@linux.ibm.com>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
> Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Minor comment below, but not a showstopper. Also, as Bharata noted
you need to hold the srcu lock for reading.
> + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
> + struct kvm_memory_slot *memslot;
> + struct kvm_memslots *slots = __kvm_memslots(kvm, i);
> +
> + if (!slots)
> + continue;
> +
> + kvm_for_each_memslot(memslot, slots)
> + kvmppc_uvmem_drop_pages(memslot, kvm, false);
> + }
Since we use the default KVM_ADDRESS_SPACE_NUM, which is 1, this code
isn't wrong but it is more verbose than it needs to be. It could be
kvm_for_each_memslot(kvm_memslots(kvm), slots)
kvmppc_uvmem_drop_pages(memslot, kvm, false);
Paul.
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-16 3:29 ` Bharata B Rao
@ 2019-12-19 21:50 ` Sukadev Bhattiprolu
0 siblings, 0 replies; 10+ messages in thread
From: Sukadev Bhattiprolu @ 2019-12-19 21:50 UTC (permalink / raw)
To: Bharata B Rao; +Cc: linuxram, kvm-ppc, linux-mm, linuxppc-dev
Bharata B Rao [bharata@linux.ibm.com] wrote:
> On Sat, Dec 14, 2019 at 06:12:08PM -0800, Sukadev Bhattiprolu wrote:
> > +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> > +{
> > + int i;
> > +
> > + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
> > + return H_UNSUPPORTED;
> > +
> > + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
> > + struct kvm_memory_slot *memslot;
> > + struct kvm_memslots *slots = __kvm_memslots(kvm, i);
> > +
> > + if (!slots)
> > + continue;
> > +
> > + kvm_for_each_memslot(memslot, slots)
> > + kvmppc_uvmem_drop_pages(memslot, kvm, false);
> > + }
>
> You need to hold srcu_read_lock(&kvm->srcu) here.
Yes, thanks! Fixed in the next version.
Sukadev
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-18 5:36 ` Paul Mackerras
@ 2019-12-19 21:51 ` Sukadev Bhattiprolu
0 siblings, 0 replies; 10+ messages in thread
From: Sukadev Bhattiprolu @ 2019-12-19 21:51 UTC (permalink / raw)
To: Paul Mackerras; +Cc: linuxram, kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
Paul Mackerras [paulus@ozlabs.org] wrote:
> On Sat, Dec 14, 2019 at 06:12:08PM -0800, Sukadev Bhattiprolu wrote:
> >
> > Implement the H_SVM_INIT_ABORT hcall which the Ultravisor can use to
> > abort an SVM after it has issued the H_SVM_INIT_START and before the
> > H_SVM_INIT_DONE hcalls. This hcall could be used when Ultravisor
> > encounters security violations or other errors when starting an SVM.
> >
> > Note that this hcall is different from UV_SVM_TERMINATE ucall which
> > is used by HV to terminate/cleanup an VM that has becore secure.
> >
> > The H_SVM_INIT_ABORT should basically undo operations that were done
> > since the H_SVM_INIT_START hcall - i.e page-out all the VM pages back
> > to normal memory, and terminate the SVM.
> >
> > (If we do not bring the pages back to normal memory, the text/data
> > of the VM would be stuck in secure memory and since the SVM did not
> > go secure, its MSR_S bit will be clear and the VM wont be able to
> > access its pages even to do a clean exit).
> >
> > Based on patches and discussion with Paul Mackerras, Ram Pai and
> > Bharata Rao.
> >
> > Signed-off-by: Ram Pai <linuxram@linux.ibm.com>
> > Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
> > Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
>
> Minor comment below, but not a showstopper. Also, as Bharata noted
> you need to hold the srcu lock for reading.
Yes, I fixed that.
>
> > + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
> > + struct kvm_memory_slot *memslot;
> > + struct kvm_memslots *slots = __kvm_memslots(kvm, i);
> > +
> > + if (!slots)
> > + continue;
> > +
> > + kvm_for_each_memslot(memslot, slots)
> > + kvmppc_uvmem_drop_pages(memslot, kvm, false);
> > + }
>
> Since we use the default KVM_ADDRESS_SPACE_NUM, which is 1, this code
> isn't wrong but it is more verbose than it needs to be. It could be
>
> kvm_for_each_memslot(kvm_memslots(kvm), slots)
> kvmppc_uvmem_drop_pages(memslot, kvm, false);
and simplified this.
Thanks.
Sukadev
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
2019-12-16 3:29 ` Bharata B Rao
2019-12-18 5:36 ` Paul Mackerras
@ 2020-01-03 0:18 ` Ram Pai
2020-01-03 0:32 ` Sukadev Bhattiprolu
2 siblings, 1 reply; 10+ messages in thread
From: Ram Pai @ 2020-01-03 0:18 UTC (permalink / raw)
To: Sukadev Bhattiprolu; +Cc: kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
On Sat, Dec 14, 2019 at 06:12:08PM -0800, Sukadev Bhattiprolu wrote:
>
> Implement the H_SVM_INIT_ABORT hcall which the Ultravisor can use to
> abort an SVM after it has issued the H_SVM_INIT_START and before the
> H_SVM_INIT_DONE hcalls. This hcall could be used when Ultravisor
> encounters security violations or other errors when starting an SVM.
>
> Note that this hcall is different from UV_SVM_TERMINATE ucall which
> is used by HV to terminate/cleanup an VM that has becore secure.
>
> The H_SVM_INIT_ABORT should basically undo operations that were done
> since the H_SVM_INIT_START hcall - i.e page-out all the VM pages back
> to normal memory, and terminate the SVM.
>
> (If we do not bring the pages back to normal memory, the text/data
> of the VM would be stuck in secure memory and since the SVM did not
> go secure, its MSR_S bit will be clear and the VM wont be able to
> access its pages even to do a clean exit).
>
> Based on patches and discussion with Paul Mackerras, Ram Pai and
> Bharata Rao.
>
> Signed-off-by: Ram Pai <linuxram@linux.ibm.com>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
> Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
> ---
> Changelog[v3]:
> - Rather than pass the NIP/MSR as parameters, load them into
> SRR0/SRR1 (like we do with other registers) and terminate
> the VM after paging out pages
> - Move the code to add a skip_page_out parameter into a
> separate patch.
>
> Changelog[v2]:
> [Paul Mackerras] avoid returning to UV "one last time" after
> the state is cleaned up. So, we now have H_SVM_INIT_ABORT:
> - take the VM's NIP/MSR register states as parameters
> - inherit the state of other registers as at UV_ESM call.
> After cleaning up the partial state, HV uses these to return
> directly to the VM with a failed UV_ESM call.
> ---
> Documentation/powerpc/ultravisor.rst | 57 +++++++++++++++++++++
> arch/powerpc/include/asm/hvcall.h | 1 +
> arch/powerpc/include/asm/kvm_book3s_uvmem.h | 6 +++
> arch/powerpc/include/asm/kvm_host.h | 1 +
> arch/powerpc/kvm/book3s_hv.c | 3 ++
> arch/powerpc/kvm/book3s_hv_uvmem.c | 24 +++++++++
> 6 files changed, 92 insertions(+)
>
> diff --git a/Documentation/powerpc/ultravisor.rst b/Documentation/powerpc/ultravisor.rst
> index 730854f73830..8c114c071bfa 100644
> --- a/Documentation/powerpc/ultravisor.rst
> +++ b/Documentation/powerpc/ultravisor.rst
> @@ -948,6 +948,63 @@ Use cases
> up its internal state for this virtual machine.
>
>
> +H_SVM_INIT_ABORT
> +----------------
> +
> + Abort the process of securing an SVM.
> +
> +Syntax
> +~~~~~~
> +
> +.. code-block:: c
> +
> + uint64_t hypercall(const uint64_t H_SVM_INIT_ABORT)
> +
> +Return values
> +~~~~~~~~~~~~~
> +
> + One of the following values:
> +
> + * H_PARAMETER on successfully cleaning up the state,
> + Hypervisor will return this value to the
> + **guest**, to indicate that the underlying
> + UV_ESM ultracall failed.
> +
> + * H_UNSUPPORTED if called from the wrong context (e.g. from
> + an SVM or before an H_SVM_INIT_START hypercall).
> +
> +Description
> +~~~~~~~~~~~
> +
> + Abort the process of securing a virtual machine. This call must
> + be made after a prior call to ``H_SVM_INIT_START`` hypercall and
> + before a call to ``H_SVM_INIT_DONE``.
> +
> + On entry into this hypercall the non-volatile GPRs and FPRs are
> + expected to contain the values they had at the time the VM issued
> + the UV_ESM ultracall. Further ``SRR0`` is expected to contain the
> + address of the instruction after the ``UV_ESM`` ultracall and ``SRR1``
> + the MSR value with which to return to the VM.
> +
> + This hypercall will cleanup any partial state that was established for
> + the VM since the prior ``H_SVM_INIT_START`` hypercall, including paging
> + out pages that were paged-into secure memory, and issue the
> + ``UV_SVM_TERMINATE`` ultracall to terminate the VM.
> +
> + After the partial state is cleaned up, control returns to the VM
> + (**not Ultravisor**), at the address specified in ``SRR0`` with the
> + MSR values set to the value in ``SRR1``.
> +
> +Use cases
> +~~~~~~~~~
> +
> + If after a successful call to ``H_SVM_INIT_START``, the Ultravisor
> + encounters an error while securing a virtual machine, either due
> + to lack of resources or because the VM's security information could
> + not be validated, Ultravisor informs the Hypervisor about it.
> + Hypervisor should use this call to clean up any internal state for
> + this virtual machine and return to the VM.
> +
> H_SVM_PAGE_IN
> -------------
>
> diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
> index 13bd870609c3..e90c073e437e 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -350,6 +350,7 @@
> #define H_SVM_PAGE_OUT 0xEF04
> #define H_SVM_INIT_START 0xEF08
> #define H_SVM_INIT_DONE 0xEF0C
> +#define H_SVM_INIT_ABORT 0xEF14
>
> /* Values for 2nd argument to H_SET_MODE */
> #define H_SET_MODE_RESOURCE_SET_CIABR 1
> diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> index 3cf8425b9838..5a9834e0e2d1 100644
> --- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> +++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h
> @@ -19,6 +19,7 @@ unsigned long kvmppc_h_svm_page_out(struct kvm *kvm,
> unsigned long kvmppc_h_svm_init_start(struct kvm *kvm);
> unsigned long kvmppc_h_svm_init_done(struct kvm *kvm);
> int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn);
> +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm);
> void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
> struct kvm *kvm, bool skip_page_out);
> #else
> @@ -62,6 +63,11 @@ static inline unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
> return H_UNSUPPORTED;
> }
>
> +static inline unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> +{
> + return H_UNSUPPORTED;
> +}
> +
> static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
> {
> return -EFAULT;
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 577ca95fac7c..8310c0407383 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -278,6 +278,7 @@ struct kvm_resize_hpt;
> /* Flag values for kvm_arch.secure_guest */
> #define KVMPPC_SECURE_INIT_START 0x1 /* H_SVM_INIT_START has been called */
> #define KVMPPC_SECURE_INIT_DONE 0x2 /* H_SVM_INIT_DONE completed */
> +#define KVMPPC_SECURE_INIT_ABORT 0x4 /* H_SVM_INIT_ABORT issued */
>
> struct kvm_arch {
> unsigned int lpid;
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 66d5312be16b..1b22f2c7ad1b 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -1099,6 +1099,9 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
> case H_SVM_INIT_DONE:
> ret = kvmppc_h_svm_init_done(vcpu->kvm);
> break;
> + case H_SVM_INIT_ABORT:
> + ret = kvmppc_h_svm_init_abort(vcpu->kvm);
> + break;
>
> default:
> return RESUME_HOST;
> diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
> index 9a5bbad7d87e..f7df8c327468 100644
> --- a/arch/powerpc/kvm/book3s_hv_uvmem.c
> +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
> @@ -287,6 +287,30 @@ void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free,
> }
> }
>
> +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> +{
> + int i;
> +
> + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
> + return H_UNSUPPORTED;
It should also return H_UNSUPPORTED when
(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) is true.
RP
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2020-01-03 0:18 ` Ram Pai
@ 2020-01-03 0:32 ` Sukadev Bhattiprolu
2020-01-03 2:20 ` Ram Pai
0 siblings, 1 reply; 10+ messages in thread
From: Sukadev Bhattiprolu @ 2020-01-03 0:32 UTC (permalink / raw)
To: Ram Pai; +Cc: kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
Ram Pai [linuxram@us.ibm.com] wrote:
> > +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> > +{
> > + int i;
> > +
> > + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
> > + return H_UNSUPPORTED;
>
> It should also return H_UNSUPPORTED when
> (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) is true.
If KVMPPC_SECURE_INIT_DONE is set, KVMPPC_SECURE_INIT_START is also
set - we never clear KVMPPC_SECURE_INIT_START right?
Sukadev
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall
2020-01-03 0:32 ` Sukadev Bhattiprolu
@ 2020-01-03 2:20 ` Ram Pai
0 siblings, 0 replies; 10+ messages in thread
From: Ram Pai @ 2020-01-03 2:20 UTC (permalink / raw)
To: Sukadev Bhattiprolu; +Cc: kvm-ppc, Bharata B Rao, linux-mm, linuxppc-dev
On Thu, Jan 02, 2020 at 04:32:33PM -0800, Sukadev Bhattiprolu wrote:
> Ram Pai [linuxram@us.ibm.com] wrote:
> > > +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
> > > +{
> > > + int i;
> > > +
> > > + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
> > > + return H_UNSUPPORTED;
> >
> > It should also return H_UNSUPPORTED when
> > (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) is true.
>
> If KVMPPC_SECURE_INIT_DONE is set, KVMPPC_SECURE_INIT_START is also
> set - we never clear KVMPPC_SECURE_INIT_START right?
I am concerned about the case, where the VM has successfully
transitioned into a SVM, where both KVMPPC_SECURE_INIT_DONE and
KVMPPC_SECURE_INIT_START are set.
In this scenario, if the UV makes a H_SVM_INIT_ABORT hcall, the
Hypervisor will not return H_UNSUPPORTED, because
KVMPPC_SECURE_INIT_START is set.
That is the reason, I think, we need to add another check as below.
if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
return H_UNSUPPORTED;
>
> Sukadev
--
Ram Pai
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2020-01-03 2:22 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
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2019-12-15 2:11 [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Sukadev Bhattiprolu
2019-12-15 2:12 ` [PATCH V3 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Sukadev Bhattiprolu
2019-12-16 3:29 ` Bharata B Rao
2019-12-19 21:50 ` Sukadev Bhattiprolu
2019-12-18 5:36 ` Paul Mackerras
2019-12-19 21:51 ` Sukadev Bhattiprolu
2020-01-03 0:18 ` Ram Pai
2020-01-03 0:32 ` Sukadev Bhattiprolu
2020-01-03 2:20 ` Ram Pai
2019-12-18 5:32 ` [PATCH V3 1/2] KVM: PPC: Add skip_page_out parameter Paul Mackerras
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