Fix issues reported by checkpatch.pl script in hv.c and
balloon.c
 - Remove unnecessary parentheses
 - Remove extra newlines
 - Remove extra spaces
 - Add spaces between comparison operators
 - Remove comparison with NULL in if statements

No functional changes intended

Signed-off-by: Aditya Nagesh <adityanagesh@linux.microsoft.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1717152521-6439-1-git-send-email-adityanagesh@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1717152521-6439-1-git-send-email-adityanagesh@linux.microsoft.com>

The Hyper-V balloon driver supports hot-add of memory in addition
to ballooning. Current code hot-adds in fixed size chunks of
128 MiB (fixed constant HA_CHUNK in the code). While this works
in Hyper-V VMs with 64 GiB or less or memory where the Linux
memblock size is 128 MiB, the hot-add fails for larger memblock
sizes because add_memory() expects memory to be added in chunks
that match the memblock size. Messages like the following are
reported when Linux has a 256 MiB memblock size:

[  312.668859] Block size [0x10000000] unaligned hotplug range:
               start 0x310000000, size 0x8000000
[  312.668880] hv_balloon: hot_add memory failed error is -22
[  312.668984] hv_balloon: Memory hot add failed

Larger memblock sizes are usually used in VMs with more than
64 GiB of memory, depending on the alignment of the VM's
physical address space.

Fix this problem by having the Hyper-V balloon driver determine
the Linux memblock size, and process hot-add requests in that
chunk size instead of a fixed 128 MiB. Also update the hot-add
alignment requested of the Hyper-V host to match the memblock
size.

The code changes look significant, but in fact are just a
simple text substitution of a new global variable for the
previous HA_CHUNK constant. No algorithms are changed except
to initialize the new global variable and to calculate the
alignment value to pass to Hyper-V. Testing with memblock
sizes of 256 MiB and 2 GiB shows correct operation.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20240503154312.142466-2-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240503154312.142466-2-mhklinux@outlook.com>

Code sequences equivalent to ALIGN(), ALIGN_DOWN(), and umin() are
currently open coded. Change these to use the kernel macro to
improve code clarity. ALIGN() and ALIGN_DOWN() require the
alignment value to be a power of 2, which is the case here.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20240503154312.142466-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240503154312.142466-1-mhklinux@outlook.com>

Pull hyperv updates from Wei Liu:

 - Support for SEV-SNP guests on Hyper-V (Tianyu Lan)

 - Support for TDX guests on Hyper-V (Dexuan Cui)

 - Use SBRM API in Hyper-V balloon driver (Mitchell Levy)

 - Avoid dereferencing ACPI root object handle in VMBus driver (Maciej
   Szmigiero)

 - A few misecllaneous fixes (Jiapeng Chong, Nathan Chancellor, Saurabh
   Sengar)

* tag 'hyperv-next-signed-20230902' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (24 commits)
  x86/hyperv: Remove duplicate include
  x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's
  x86/hyperv: Remove hv_isolation_type_en_snp
  x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor
  Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor
  x86/hyperv: Introduce a global variable hyperv_paravisor_present
  Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM
  x86/hyperv: Fix serial console interrupts for fully enlightened TDX guests
  Drivers: hv: vmbus: Support fully enlightened TDX guests
  x86/hyperv: Support hypercalls for fully enlightened TDX guests
  x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests
  x86/hyperv: Fix undefined reference to isolation_type_en_snp without CONFIG_HYPERV
  x86/hyperv: Add missing 'inline' to hv_snp_boot_ap() stub
  hv: hyperv.h: Replace one-element array with flexible-array member
  Drivers: hv: vmbus: Don't dereference ACPI root object handle
  x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES
  x86/hyperv: Add smp support for SEV-SNP guest
  clocksource: hyper-v: Mark hyperv tsc page unencrypted in sev-snp enlightened guest
  x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest
  drivers: hv: Mark percpu hvcall input arg page unencrypted in SEV-SNP enlightened guest
  ...

This patch is intended as a proof-of-concept for the new SBRM
machinery[1]. For some brief background, the idea behind SBRM is using
the __cleanup__ attribute to automatically unlock locks (or otherwise
release resources) when they go out of scope, similar to C++ style RAII.
This promises some benefits such as making code simpler (particularly
where you have lots of goto fail; type constructs) as well as reducing
the surface area for certain kinds of bugs.

The changes in this patch should not result in any difference in how the
code actually runs (i.e., it's purely an exercise in this new syntax
sugar). In one instance SBRM was not appropriate, so I left that part
alone, but all other locking/unlocking is handled automatically in this
patch.

[1] https://lore.kernel.org/all/20230626125726.GU4253@hirez.programming.kicks-ass.net/

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: "Mitchell Levy (Microsoft)" <levymitchell0@gmail.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230807-sbrm-hyperv-v2-1-9d2ac15305bd@gmail.com

Several places in code for Hyper-V reference the
per-CPU variable hyperv_pcpu_input_arg. Older code uses a multi-line
sequence to reference the variable, and usually includes a cast.
Newer code does a much simpler direct assignment. The latter is
preferable as the complexity of the older code is unnecessary.

Update older code to use the simpler direct assignment.

Signed-off-by: Nischala Yelchuri <niyelchu@linux.microsoft.com>
Link: https://lore.kernel.org/r/1687286438-9421-1-git-send-email-niyelchu@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Pull hyperv updates from Wei Liu:

 - allow Linux to run as the nested root partition for Microsoft
   Hypervisor (Jinank Jain and Nuno Das Neves)

 - clean up the return type of callback functions (Dawei Li)

* tag 'hyperv-next-signed-20230220' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Fix hv_get/set_register for nested bringup
  Drivers: hv: Make remove callback of hyperv driver void returned
  Drivers: hv: Enable vmbus driver for nested root partition
  x86/hyperv: Add an interface to do nested hypercalls
  Drivers: hv: Setup synic registers in case of nested root partition
  x86/hyperv: Add support for detecting nested hypervisor

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Dexuan Cui <decui@microsoft.com>
Fixes: d180e0a1be6c ("Drivers: hv: Create debugfs file with hyper-v balloon usage information")
Cc: stable <stable@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230202140918.2289522-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit fc7a6209d571 ("bus: Make remove callback return
void") forces bus_type::remove be void-returned, it doesn't
make much sense for any bus based driver implementing remove
callbalk to return non-void to its caller.

As such, change the remove function for Hyper-V VMBus based
drivers to return void.

Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Link: https://lore.kernel.org/r/TYCP286MB2323A93C55526E4DF239D3ACCAFA9@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Newer versions of Hyper-V allow reporting unused guest pages in chunks
smaller than 2 Mbytes.  Using smaller chunks allows reporting more
unused guest pages, but with increased overhead in the finding the
small chunks.  To make this tradeoff configurable, use the existing
page_reporting_order module parameter to control the reporting order.
Drop and refine checks that restricted the minimun page reporting order
to 2Mbytes size pages. Add appropriate checks to make sure the
underlying Hyper-V versions support cold discard hints of any order
(and not just starting from 9)

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1664517699-1085-3-git-send-email-shradhagupta@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>