| From: |
| Vishal Annapurve <vannapurve-AT-google.com> |
| To: |
| x86-AT-kernel.org, linux-kernel-AT-vger.kernel.org |
| Subject: |
| [PATCH V4 0/4] x86/tdx: Route safe halt execution via tdx_safe_halt() |
| Date: |
| Wed, 12 Feb 2025 00:07:43 +0000 |
| Message-ID: |
| <20250212000747.3403836-1-vannapurve@google.com> |
| Cc: |
| pbonzini-AT-redhat.com, seanjc-AT-google.com, erdemaktas-AT-google.com, ackerleytng-AT-google.com, jxgao-AT-google.com, sagis-AT-google.com, oupton-AT-google.com, pgonda-AT-google.com, kirill-AT-shutemov.name, dave.hansen-AT-linux.intel.com, linux-coco-AT-lists.linux.dev, chao.p.peng-AT-linux.intel.com, isaku.yamahata-AT-gmail.com, sathyanarayanan.kuppuswamy-AT-linux.intel.com, Vishal Annapurve <vannapurve-AT-google.com> |
| Archive-link: |
| Article |
Direct HLT instruction execution causes #VEs for TDX VMs which is routed
to hypervisor via TDCALL. safe_halt() routines execute HLT in STI-shadow
so IRQs need to remain disabled until the TDCALL to ensure that pending
IRQs are correctly treated as wake events. So "sti;hlt" sequence needs to
be replaced with "TDCALL; raw_local_irq_enable()" for TDX VMs.
Changes introduced by the series include:
- Move *halt() variants outside CONFIG_PARAVIRT_XXL and under
CONFIG_PARAVIRT [1].
- Route "sti; hlt" sequences via tdx_safe_halt() for reliability.
- Route "hlt" sequences via tdx_halt() to avoid unnecessary #VEs.
- Add explicit dependency on CONFIG_PARAVIRT for TDX VMs.
- Warn and fail emulation if HLT #VE emulation executes with interrupts
enabled.
- Clean up TDX specific idle routine override.
Changes since v3:
1) Addressed comments from Sean.
2) Included [1] in the series to fix the scenarios where
CONFIG_PARAVIRT_XXL could be disabled.
v3: https://lore.kernel.org/all/20250206222714.1079059-1-vann...
[1] https://lore.kernel.org/lkml/20210517235008.257241-1-sath...
Kirill A. Shutemov (1):
x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT
Vishal Annapurve (3):
x86/tdx: Route safe halt execution via tdx_safe_halt()
x86/tdx: Emit warning if IRQs are enabled during HLT #VE handling
x86/tdx: Remove TDX specific idle routine
arch/x86/Kconfig | 1 +
arch/x86/coco/tdx/tdx.c | 26 ++++++++++++++++-
arch/x86/include/asm/irqflags.h | 40 +++++++++++++++------------
arch/x86/include/asm/paravirt.h | 20 +++++++-------
arch/x86/include/asm/paravirt_types.h | 3 +-
arch/x86/include/asm/tdx.h | 2 --
arch/x86/kernel/paravirt.c | 14 ++++++----
arch/x86/kernel/process.c | 3 --
8 files changed, 67 insertions(+), 42 deletions(-)
--
2.48.1.502.g6dc24dfdaf-goog
