Vishal Annapurve 805e3ce5e0 x86/tdx: Fix arch_safe_halt() execution for TDX VMs ... commit 9f98a4f4e7 upstream. Direct HLT instruction execution causes #VEs for TDX VMs which is routed to hypervisor via TDCALL. If HLT is executed in STI-shadow, resulting #VE handler will enable interrupts before TDCALL is routed to hypervisor leading to missed wakeup events, as current TDX spec doesn't expose interruptibility state information to allow #VE handler to selectively enable interrupts. Commit bfe6ed0c67 ("x86/tdx: Add HLT support for TDX guests") prevented the idle routines from executing HLT instruction in STI-shadow. But it missed the paravirt routine which can be reached via this path as an example: kvm_wait() => safe_halt() => raw_safe_halt() => arch_safe_halt() => irq.safe_halt() => pv_native_safe_halt() To reliably handle arch_safe_halt() for TDX VMs, introduce explicit dependency on CONFIG_PARAVIRT and override paravirt halt()/safe_halt() routines with TDX-safe versions that execute direct TDCALL and needed interrupt flag updates. Executing direct TDCALL brings in additional benefit of avoiding HLT related #VEs altogether. As tested by Ryan Afranji: "Tested with the specjbb2015 benchmark. It has heavy lock contention which leads to many halt calls. TDX VMs suffered a poor score before this patchset. Verified the major performance improvement with this patchset applied." Fixes: bfe6ed0c67 ("x86/tdx: Add HLT support for TDX guests") Signed-off-by: Vishal Annapurve <vannapurve@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Ryan Afranji <afranji@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250228014416.3925664-3-vannapurve@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2025-04-10 14:39:37 +02:00
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sev	x86/sev: Fix __reserved field in sev_config	2024-07-30 10:07:26 +02:00
tdx	x86/tdx: Fix arch_safe_halt() execution for TDX VMs	2025-04-10 14:39:37 +02:00
core.c	cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup	2024-06-17 17:45:34 +02:00
Makefile	x86/sev: Move SEV compilation units	2024-07-11 11:55:58 +02:00