When a Linux VM runs on Hyper-V and hibernates, it must disable the memory hot-add/remove and balloon up/down capabilities in the hv_balloon driver.
By default, Hyper-V does not enable the virtual ACPI S4 state for a VM; on recent Hyper-V hosts, the administrator is able to enable the virtual ACPI S4 state for a VM, so we hope to use the presence of the virtual ACPI S4 state as a hint for hv_balloon to disable the aforementioned capabilities. The new API will be used by hv_balloon. Signed-off-by: Dexuan Cui <[email protected]> --- arch/x86/hyperv/hv_init.c | 7 +++++++ include/asm-generic/mshyperv.h | 2 ++ 2 files changed, 9 insertions(+) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 78e53d9..6735e45 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -7,6 +7,7 @@ * Author : K. Y. Srinivasan <[email protected]> */ +#include <linux/acpi.h> #include <linux/efi.h> #include <linux/types.h> #include <asm/apic.h> @@ -453,3 +454,9 @@ bool hv_is_hyperv_initialized(void) return hypercall_msr.enable; } EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); + +bool hv_is_hibernation_supported(void) +{ + return acpi_sleep_state_supported(ACPI_STATE_S4); +} +EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 0becb7d..1cb4001 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -166,9 +166,11 @@ static inline int cpumask_to_vpset(struct hv_vpset *vpset, void hyperv_report_panic(struct pt_regs *regs, long err); void hyperv_report_panic_msg(phys_addr_t pa, size_t size); bool hv_is_hyperv_initialized(void); +bool hv_is_hibernation_supported(void); void hyperv_cleanup(void); #else /* CONFIG_HYPERV */ static inline bool hv_is_hyperv_initialized(void) { return false; } +static inline bool hv_is_hibernation_supported(void) { return false; } static inline void hyperv_cleanup(void) {} #endif /* CONFIG_HYPERV */ -- 1.8.3.1
