[PULL 0/3] Misc changes for 2022-04-05

[PULL 0/3] Misc changes for 2022-04-05

[Paolo Bonzini]

The following changes since commit 20661b75ea6093f5e59079d00a778a972d6732c5:

  Merge tag 'pull-ppc-20220404' of https://github.com/legoater/qemu into staging (2022-04-04 15:48:55 +0100)

are available in the Git repository at:

  https://gitlab.com/bonzini/qemu.git tags/for-upstream

for you to fetch changes up to 776a6a32b4982a68d3b7a77cbfaae6c2b363a0b8:

  docs/system/i386: Add measurement calculation details to amd-memory-encryption (2022-04-05 10:42:06 +0200)

----------------------------------------------------------------
* fix vss-win32 compilation with clang++

* update Coverity model

* add measurement calculation to amd-memory-encryption docs

----------------------------------------------------------------
Dov Murik (1):
      docs/system/i386: Add measurement calculation details to amd-memory-encryption

Helge Konetzka (1):
      qga/vss-win32: fix compilation with clang++

Paolo Bonzini (1):
      coverity: update model for latest tools

 docs/system/i386/amd-memory-encryption.rst | 54 +++++++++++++++++++++++++++---
 qga/vss-win32/install.cpp                  |  3 +-
 scripts/coverity-scan/model.c              |  3 +-
 3 files changed, 54 insertions(+), 6 deletions(-)
-- 
2.35.1

[PULL 1/3] coverity: update model for latest tools

[Paolo Bonzini]

Coverity is now rejecting incomplete types in the modeling file.
Just use a random number (in the neighborhood of the actual one)
for the size of a GIOChannel.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 scripts/coverity-scan/model.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/coverity-scan/model.c b/scripts/coverity-scan/model.c
index 9d4fba53d9..686d1a3008 100644
--- a/scripts/coverity-scan/model.c
+++ b/scripts/coverity-scan/model.c
@@ -356,7 +356,8 @@ int g_poll (GPollFD *fds, unsigned nfds, int timeout)
 typedef struct _GIOChannel GIOChannel;
 GIOChannel *g_io_channel_unix_new(int fd)
 {
-    GIOChannel *c = g_malloc0(sizeof(GIOChannel));
+    /* cannot use incomplete type, the actual struct is roughly this size.  */
+    GIOChannel *c = g_malloc0(20 * sizeof(void *));
     __coverity_escape__(fd);
     return c;
 }
-- 
2.35.1

[PULL 2/3] qga/vss-win32: fix compilation with clang++

[Paolo Bonzini]

From: Helge Konetzka <hk@zapateado.de>

This fixes:

qga/vss-win32/install.cpp:49:24: error: cannot initialize a variable of
type 'char *' with an rvalue of type 'const char *'
    char *msg = NULL, *nul = strchr(text, '(');
                       ^     ~~~~~~~~~~~~~~~~~

Signed-off-by: Helge Konetzka <hk@zapateado.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Message-Id: <39400817-3dc9-516d-9096-bc1f68862531@zapateado.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 qga/vss-win32/install.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
index 8076efe3cb..b57508fbe0 100644
--- a/qga/vss-win32/install.cpp
+++ b/qga/vss-win32/install.cpp
@@ -46,7 +46,8 @@ void errmsg(DWORD err, const char *text)
      * If text doesn't contains '(', negative precision is given, which is
      * treated as though it were missing.
      */
-    char *msg = NULL, *nul = strchr(text, '(');
+    char *msg = NULL;
+    const char *nul = strchr(text, '(');
     int len = nul ? nul - text : -1;
 
     FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
-- 
2.35.1

[PULL 3/3] docs/system/i386: Add measurement calculation details to amd-memory-encryption

[Paolo Bonzini]

From: Dov Murik <dovmurik@linux.ibm.com>

Add a section explaining how the Guest Owner should calculate the
expected guest launch measurement for SEV and SEV-ES.

Also update the name and links to the SEV API Spec document.

Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20220217110059.2320497-1-dovmurik@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 docs/system/i386/amd-memory-encryption.rst | 54 ++++++++++++++++++++--
 1 file changed, 50 insertions(+), 4 deletions(-)

diff --git a/docs/system/i386/amd-memory-encryption.rst b/docs/system/i386/amd-memory-encryption.rst
index 215946f813..dcf4add0e7 100644
--- a/docs/system/i386/amd-memory-encryption.rst
+++ b/docs/system/i386/amd-memory-encryption.rst
@@ -47,7 +47,7 @@ The guest policy is passed as plaintext. A hypervisor may choose to read it,
 but should not modify it (any modification of the policy bits will result
 in bad measurement). The guest policy is a 4-byte data structure containing
 several flags that restricts what can be done on a running SEV guest.
-See KM Spec section 3 and 6.2 for more details.
+See SEV API Spec ([SEVAPI]_) section 3 and 6.2 for more details.
 
 The guest policy can be provided via the ``policy`` property::
 
@@ -92,7 +92,7 @@ expects.
 ``LAUNCH_FINISH`` finalizes the guest launch and destroys the cryptographic
 context.
 
-See SEV KM API Spec ([SEVKM]_) 'Launching a guest' usage flow (Appendix A) for the
+See SEV API Spec ([SEVAPI]_) 'Launching a guest' usage flow (Appendix A) for the
 complete flow chart.
 
 To launch a SEV guest::
@@ -118,6 +118,49 @@ a SEV-ES guest:
  - Requires in-kernel irqchip - the burden is placed on the hypervisor to
    manage booting APs.
 
+Calculating expected guest launch measurement
+---------------------------------------------
+
+In order to verify the guest launch measurement, The Guest Owner must compute
+it in the exact same way as it is calculated by the AMD-SP.  SEV API Spec
+([SEVAPI]_) section 6.5.1 describes the AMD-SP operations:
+
+    GCTX.LD is finalized, producing the hash digest of all plaintext data
+    imported into the guest.
+
+    The launch measurement is calculated as:
+
+    HMAC(0x04 || API_MAJOR || API_MINOR || BUILD || GCTX.POLICY || GCTX.LD || MNONCE; GCTX.TIK)
+
+    where "||" represents concatenation.
+
+The values of API_MAJOR, API_MINOR, BUILD, and GCTX.POLICY can be obtained
+from the ``query-sev`` qmp command.
+
+The value of MNONCE is part of the response of ``query-sev-launch-measure``: it
+is the last 16 bytes of the base64-decoded data field (see SEV API Spec
+([SEVAPI]_) section 6.5.2 Table 52: LAUNCH_MEASURE Measurement Buffer).
+
+The value of GCTX.LD is
+``SHA256(firmware_blob || kernel_hashes_blob || vmsas_blob)``, where:
+
+* ``firmware_blob`` is the content of the entire firmware flash file (for
+  example, ``OVMF.fd``).  Note that you must build a stateless firmware file
+  which doesn't use an NVRAM store, because the NVRAM area is not measured, and
+  therefore it is not secure to use a firmware which uses state from an NVRAM
+  store.
+* if kernel is used, and ``kernel-hashes=on``, then ``kernel_hashes_blob`` is
+  the content of PaddedSevHashTable (including the zero padding), which itself
+  includes the hashes of kernel, initrd, and cmdline that are passed to the
+  guest.  The PaddedSevHashTable struct is defined in ``target/i386/sev.c``.
+* if SEV-ES is enabled (``policy & 0x4 != 0``), ``vmsas_blob`` is the
+  concatenation of all VMSAs of the guest vcpus.  Each VMSA is 4096 bytes long;
+  its content is defined inside Linux kernel code as ``struct vmcb_save_area``,
+  or in AMD APM Volume 2 ([APMVOL2]_) Table B-2: VMCB Layout, State Save Area.
+
+If kernel hashes are not used, or SEV-ES is disabled, use empty blobs for
+``kernel_hashes_blob`` and ``vmsas_blob`` as needed.
+
 Debugging
 ---------
 
@@ -142,8 +185,11 @@ References
 `AMD Memory Encryption whitepaper
 <https://developer.amd.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf>`_
 
-.. [SEVKM] `Secure Encrypted Virtualization Key Management
-   <http://developer.amd.com/wordpress/media/2017/11/55766_SEV-KM-API_Specification.pdf>`_
+.. [SEVAPI] `Secure Encrypted Virtualization API
+   <https://www.amd.com/system/files/TechDocs/55766_SEV-KM_API_Specification.pdf>`_
+
+.. [APMVOL2] `AMD64 Architecture Programmer's Manual Volume 2: System Programming
+   <https://www.amd.com/system/files/TechDocs/24593.pdf>`_
 
 KVM Forum slides:
 
-- 
2.35.1

Re: [PULL 0/3] Misc changes for 2022-04-05

[Peter Maydell]

On Tue, 5 Apr 2022 at 10:25, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> The following changes since commit 20661b75ea6093f5e59079d00a778a972d6732c5:
>
>   Merge tag 'pull-ppc-20220404' of https://github.com/legoater/qemu into staging (2022-04-04 15:48:55 +0100)
>
> are available in the Git repository at:
>
>   https://gitlab.com/bonzini/qemu.git tags/for-upstream
>
> for you to fetch changes up to 776a6a32b4982a68d3b7a77cbfaae6c2b363a0b8:
>
>   docs/system/i386: Add measurement calculation details to amd-memory-encryption (2022-04-05 10:42:06 +0200)
>
> ----------------------------------------------------------------
> * fix vss-win32 compilation with clang++
>
> * update Coverity model
>
> * add measurement calculation to amd-memory-encryption docs
>
> ----------------------------------------------------------------

Hi; this tag doesn't match what your pullreq cover letter claims
it is -- it is pointing at 267b85d4e3d15, not 776a6a32b49, and
it has way more than 3 patches in it.

thanks
-- PMM

Re: [PULL 0/3] Misc changes for 2022-04-05

[Peter Maydell]

On Tue, 5 Apr 2022 at 10:25, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> The following changes since commit 20661b75ea6093f5e59079d00a778a972d6732c5:
>
>   Merge tag 'pull-ppc-20220404' of https://github.com/legoater/qemu into staging (2022-04-04 15:48:55 +0100)
>
> are available in the Git repository at:
>
>   https://gitlab.com/bonzini/qemu.git tags/for-upstream
>
> for you to fetch changes up to 776a6a32b4982a68d3b7a77cbfaae6c2b363a0b8:
>
>   docs/system/i386: Add measurement calculation details to amd-memory-encryption (2022-04-05 10:42:06 +0200)
>
> ----------------------------------------------------------------
> * fix vss-win32 compilation with clang++
>
> * update Coverity model
>
> * add measurement calculation to amd-memory-encryption docs
>
> ----------------------------------------------------------------
> Dov Murik (1):
>       docs/system/i386: Add measurement calculation details to amd-memory-encryption
>
> Helge Konetzka (1):
>       qga/vss-win32: fix compilation with clang++
>
> Paolo Bonzini (1):
>       coverity: update model for latest tools


Applied, thanks.

Please update the changelog at https://wiki.qemu.org/ChangeLog/7.0
for any user-visible changes.

-- PMM