| Message ID | 20210609215047.1955866-6-sathyanarayanan.kuppuswamy@linux.intel.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | None | expand |
On Wed, Jun 9, 2021 at 11:51 PM Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > VM guests that supports ACPI, use standard ACPI mechanisms to signal > sleep state entry (including reboot) to the host. The ACPI > specification mandates WBINVD on any sleep state entry with the > expectation that the platform is only responsible for maintaining the > state of memory over sleep states, not preserving dirty data in any > CPU caches. ACPI cache flushing requirements pre-date the advent of > virtualization. Given guest sleep state entry does not affect any > host power rails it is not required to flush caches. The host is > responsible for maintaining cache state over its own bare metal sleep > state transitions that power-off the cache. A TDX guest, unlike a > typical guest, will machine check if the CPU cache is powered off. > > Cc: Rafael J. Wysocki <rjw@rjwysocki.net> > Cc: linux-acpi@vger.kernel.org > Reviewed-by: Dan Williams <dan.j.williams@intel.com> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > arch/x86/include/asm/acenv.h | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/acenv.h b/arch/x86/include/asm/acenv.h > index 9aff97f0de7f..d4162e94bee8 100644 > --- a/arch/x86/include/asm/acenv.h > +++ b/arch/x86/include/asm/acenv.h > @@ -10,10 +10,15 @@ > #define _ASM_X86_ACENV_H > > #include <asm/special_insns.h> > +#include <asm/cpu.h> > > /* Asm macros */ > > -#define ACPI_FLUSH_CPU_CACHE() wbinvd() > +#define ACPI_FLUSH_CPU_CACHE() \ > +do { \ > + if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) \ > + wbinvd(); \ > +} while (0) > > int __acpi_acquire_global_lock(unsigned int *lock); > int __acpi_release_global_lock(unsigned int *lock); > -- > 2.25.1 >
diff --git a/arch/x86/include/asm/acenv.h b/arch/x86/include/asm/acenv.h index 9aff97f0de7f..d4162e94bee8 100644 --- a/arch/x86/include/asm/acenv.h +++ b/arch/x86/include/asm/acenv.h @@ -10,10 +10,15 @@ #define _ASM_X86_ACENV_H #include <asm/special_insns.h> +#include <asm/cpu.h> /* Asm macros */ -#define ACPI_FLUSH_CPU_CACHE() wbinvd() +#define ACPI_FLUSH_CPU_CACHE() \ +do { \ + if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) \ + wbinvd(); \ +} while (0) int __acpi_acquire_global_lock(unsigned int *lock); int __acpi_release_global_lock(unsigned int *lock);