linux-toradex.git/arch/x86/hyperv, branch v5.16-rc5

x86/hyperv: Move required MSRs check to initial platform probing

2021-11-15T12:37:08+00:00

Explicitly check for MSR_HYPERCALL and MSR_VP_INDEX support when probing
for running as a Hyper-V guest instead of waiting until hyperv_init() to
detect the bogus configuration.  Add messages to give the admin a heads
up that they are likely running on a broken virtual machine setup.

At best, silently disabling Hyper-V is confusing and difficult to debug,
e.g. the kernel _says_ it's using all these fancy Hyper-V features, but
always falls back to the native versions.  At worst, the half baked setup
will crash/hang the kernel.

Reviewed-by: Vitaly Kuznetsov 
Signed-off-by: Sean Christopherson 
Link: https://lore.kernel.org/r/20211104182239.1302956-3-seanjc@google.com
Signed-off-by: Wei Liu

x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails

2021-11-15T12:37:08+00:00

Check for a valid hv_vp_index array prior to derefencing hv_vp_index when
setting Hyper-V's TSC change callback.  If Hyper-V setup failed in
hyperv_init(), the kernel will still report that it's running under
Hyper-V, but will have silently disabled nearly all functionality.

  BUG: kernel NULL pointer dereference, address: 0000000000000010
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP
  CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc2+ #75
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:set_hv_tscchange_cb+0x15/0xa0
  Code: <8b> 04 82 8b 15 12 17 85 01 48 c1 e0 20 48 0d ee 00 01 00 f6 c6 08
  ...
  Call Trace:
   kvm_arch_init+0x17c/0x280
   kvm_init+0x31/0x330
   vmx_init+0xba/0x13a
   do_one_initcall+0x41/0x1c0
   kernel_init_freeable+0x1f2/0x23b
   kernel_init+0x16/0x120
   ret_from_fork+0x22/0x30

Fixes: 93286261de1b ("x86/hyperv: Reenlightenment notifications support")
Cc: stable@vger.kernel.org
Cc: Vitaly Kuznetsov 
Signed-off-by: Sean Christopherson 
Reviewed-by: Vitaly Kuznetsov 
Link: https://lore.kernel.org/r/20211104182239.1302956-2-seanjc@google.com
Signed-off-by: Wei Liu

x86/hyperv: Protect set_hv_tscchange_cb() against getting preempted

2021-10-28T11:59:13+00:00

The following issue is observed with CONFIG_DEBUG_PREEMPT when KVM loads:

 KVM: vmx: using Hyper-V Enlightened VMCS
 BUG: using smp_processor_id() in preemptible [00000000] code: systemd-udevd/488
 caller is set_hv_tscchange_cb+0x16/0x80
 CPU: 1 PID: 488 Comm: systemd-udevd Not tainted 5.15.0-rc5+ #396
 Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019
 Call Trace:
  dump_stack_lvl+0x6a/0x9a
  check_preemption_disabled+0xde/0xe0
  ? kvm_gen_update_masterclock+0xd0/0xd0 [kvm]
  set_hv_tscchange_cb+0x16/0x80
  kvm_arch_init+0x23f/0x290 [kvm]
  kvm_init+0x30/0x310 [kvm]
  vmx_init+0xaf/0x134 [kvm_intel]
  ...

set_hv_tscchange_cb() can get preempted in between acquiring
smp_processor_id() and writing to HV_X64_MSR_REENLIGHTENMENT_CONTROL. This
is not an issue by itself: HV_X64_MSR_REENLIGHTENMENT_CONTROL is a
partition-wide MSR and it doesn't matter which particular CPU will be
used to receive reenlightenment notifications. The only real problem can
(in theory) be observed if the CPU whose id was acquired with
smp_processor_id() goes offline before we manage to write to the MSR,
the logic in hv_cpu_die() won't be able to reassign it correctly.

Reported-by: Michael Kelley 
Signed-off-by: Vitaly Kuznetsov 
Link: https://lore.kernel.org/r/20211012155005.1613352-1-vkuznets@redhat.com
Signed-off-by: Wei Liu

x86/hyperv: Remove duplicate include

2021-10-28T11:36:34+00:00

Clean up the following includecheck warning:

./arch/x86/hyperv/ivm.c: linux/bitfield.h is included more than once.
./arch/x86/hyperv/ivm.c: linux/types.h is included more than once.

Reported-by: Abaci Robot 
Signed-off-by: Jiapeng Chong 
Link: https://lore.kernel.org/r/1635325022-99889-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Wei Liu

x86/hyperv: Remove duplicated include in hv_init

2021-10-28T11:27:58+00:00

Fix following checkinclude.pl warning:
./arch/x86/hyperv/hv_init.c: linux/io.h is included more than once.

The include is in line 13. Remove the duplicated here.

Signed-off-by: Wan Jiabing 
Link: https://lore.kernel.org/r/20211026113249.30481-1-wanjiabing@vivo.com
Signed-off-by: Wei Liu

x86/hyperv: Add ghcb hvcall support for SNP VM

2021-10-28T11:22:49+00:00

hyperv provides ghcb hvcall to handle VMBus
HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
msg in SNP Isolation VM. Add such support.

Reviewed-by: Michael Kelley 
Signed-off-by: Tianyu Lan 
Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com
Signed-off-by: Wei Liu

x86/hyperv: Add Write/Read MSR registers via ghcb page

2021-10-28T11:22:38+00:00

Hyperv provides GHCB protocol to write Synthetic Interrupt
Controller MSR registers in Isolation VM with AMD SEV SNP
and these registers are emulated by hypervisor directly.
Hyperv requires to write SINTx MSR registers twice. First
writes MSR via GHCB page to communicate with hypervisor
and then writes wrmsr instruction to talk with paravisor
which runs in VMPL0. Guest OS ID MSR also needs to be set
via GHCB page.

Reviewed-by: Michael Kelley 
Signed-off-by: Tianyu Lan 
Link: https://lore.kernel.org/r/20211025122116.264793-7-ltykernel@gmail.com
Signed-off-by: Wei Liu

x86/hyperv: Add new hvcall guest address host visibility support

2021-10-28T11:21:33+00:00

Add new hvcall guest address host visibility support to mark
memory visible to host. Call it inside set_memory_decrypted
/encrypted(). Add HYPERVISOR feature check in the
hv_is_isolation_supported() to optimize in non-virtualization
environment.

Acked-by: Dave Hansen 
Reviewed-by: Michael Kelley 
Signed-off-by: Tianyu Lan 
Link: https://lore.kernel.org/r/20211025122116.264793-4-ltykernel@gmail.com
[ wei: fix conflicts with tip ]
Signed-off-by: Wei Liu

x86/hyperv: Initialize GHCB page in Isolation VM

2021-10-28T10:47:52+00:00

Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest
to communicate with hypervisor. Map GHCB page for all
cpus to read/write MSR register and submit hvcall request
via ghcb page.

Reviewed-by: Michael Kelley 
Signed-off-by: Tianyu Lan 
Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com
Signed-off-by: Wei Liu

Merge tag 'hyperv-fixes-signed-20211007' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

2021-10-07T16:44:48+00:00

Pull hyperv fixes from Wei Liu:

 - Replace uuid.h with types.h in a header (Andy Shevchenko)

 - Avoid sleeping in atomic context in PCI driver (Long Li)

 - Avoid sending IPI to self when it shouldn't (Vitaly Kuznetsov)

* tag 'hyperv-fixes-signed-20211007' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Avoid erroneously sending IPI to 'self'
  hyper-v: Replace uuid.h with types.h
  PCI: hv: Fix sleep while in non-sleep context when removing child devices from the bus