[Qemu-devel] [PATCH v2 0/2] Fix SEV VM device assignment

[Qemu-devel] [PATCH v2 0/2] Fix SEV VM device assignment

[Singh, Brijesh]

Fix: https://bugzilla.redhat.com/show_bug.cgi?id=1667249

Since v1:
 * check the error code from memory_region_from_host() before
   accessing the mr.

Brijesh Singh (2):
  memory: Fix the memory region type assignment order
  target/i386: sev: Do not pin the ram device memory region

 memory.c          |  9 ++++++++-
 target/i386/sev.c | 11 +++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

-- 
2.17.1

[Qemu-devel] [PATCH v2 1/2] memory: Fix the memory region type assignment order

[Singh, Brijesh]

Currently, a callback registered through the RAMBlock notifier
is not able to get the memory region type (i.e callback is not
able to use memory_region_is_ram_device function). This is
because mr->ram assignment happens _after_ the memory is allocated
whereas the callback is executed during allocation.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1667249
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 memory.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/memory.c b/memory.c
index 61d66e4441..9ec15349dd 100644
--- a/memory.c
+++ b/memory.c
@@ -1652,10 +1652,17 @@ void memory_region_init_ram_device_ptr(MemoryRegion *mr,
                                        uint64_t size,
                                        void *ptr)
 {
-    memory_region_init_ram_ptr(mr, owner, name, size, ptr);
+    memory_region_init(mr, owner, name, size);
+    mr->ram = true;
+    mr->terminates = true;
     mr->ram_device = true;
     mr->ops = &ram_device_mem_ops;
     mr->opaque = mr;
+    mr->destructor = memory_region_destructor_ram;
+    mr->dirty_log_mask = tcg_enabled() ? (1 << DIRTY_MEMORY_CODE) : 0;
+    /* qemu_ram_alloc_from_ptr cannot fail with ptr != NULL.  */
+    assert(ptr != NULL);
+    mr->ram_block = qemu_ram_alloc_from_ptr(size, ptr, mr, &error_fatal);
 }
 
 void memory_region_init_alias(MemoryRegion *mr,
-- 
2.17.1

[Qemu-devel] [PATCH v2 2/2] target/i386: sev: Do not pin the ram device memory region

[Singh, Brijesh]

The RAM device presents a memory region that should be handled
as an IO region and should not be pinned.

In the case of the vfio-pci, RAM device represents a MMIO BAR
and the memory region is not backed by pages hence
KVM_MEMORY_ENCRYPT_REG_REGION fails to lock the memory range.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1667249
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 target/i386/sev.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 20b2d325d8..cd77f6b5d4 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -131,6 +131,17 @@ sev_ram_block_added(RAMBlockNotifier *n, void *host, size_t size)
 {
     int r;
     struct kvm_enc_region range;
+    ram_addr_t offset;
+    MemoryRegion *mr;
+
+    /*
+     * The RAM device presents a memory region that should be treated
+     * as IO region and should not be pinned.
+     */
+    mr = memory_region_from_host(host, &offset);
+    if (mr && memory_region_is_ram_device(mr)) {
+        return;
+    }
 
     range.addr = (__u64)(unsigned long)host;
     range.size = size;
-- 
2.17.1

Re: [Qemu-devel] [PATCH v2 2/2] target/i386: sev: Do not pin the ram device memory region

[Alex Williamson]

On Mon, 4 Feb 2019 22:23:40 +0000
"Singh, Brijesh" <brijesh.singh@amd.com> wrote:

> The RAM device presents a memory region that should be handled
> as an IO region and should not be pinned.
> 
> In the case of the vfio-pci, RAM device represents a MMIO BAR
> and the memory region is not backed by pages hence
> KVM_MEMORY_ENCRYPT_REG_REGION fails to lock the memory range.
> 
> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1667249
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
>  target/i386/sev.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index 20b2d325d8..cd77f6b5d4 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -131,6 +131,17 @@ sev_ram_block_added(RAMBlockNotifier *n, void *host, size_t size)
>  {
>      int r;
>      struct kvm_enc_region range;
> +    ram_addr_t offset;
> +    MemoryRegion *mr;
> +
> +    /*
> +     * The RAM device presents a memory region that should be treated
> +     * as IO region and should not be pinned.
> +     */
> +    mr = memory_region_from_host(host, &offset);
> +    if (mr && memory_region_is_ram_device(mr)) {
> +        return;
> +    }
>  
>      range.addr = (__u64)(unsigned long)host;
>      range.size = size;

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>

Re: [Qemu-devel] [PATCH v2 0/2] Fix SEV VM device assignment

[Singh, Brijesh]

Hi Paolo,

Any comment on this series. Currently, device pass-through is
broken for the SEV guests. I am wondering if we can queue the
patches.

thanks
Brijesh

On 2/4/19 4:23 PM, Singh, Brijesh wrote:
> Fix: https://bugzilla.redhat.com/show_bug.cgi?id=1667249
> 
> Since v1:
>   * check the error code from memory_region_from_host() before
>     accessing the mr.
> 
> Brijesh Singh (2):
>    memory: Fix the memory region type assignment order
>    target/i386: sev: Do not pin the ram device memory region
> 
>   memory.c          |  9 ++++++++-
>   target/i386/sev.c | 11 +++++++++++
>   2 files changed, 19 insertions(+), 1 deletion(-)
>