diff options
author | Sunil Muthuswamy <sunilmut@microsoft.com> | 2021-03-23 21:47:16 +0300 |
---|---|---|
committer | Wei Liu <wei.liu@kernel.org> | 2021-03-24 14:35:24 +0300 |
commit | 6dc2a774cb4fdb524b7eb0b8db74198a1b4815ea (patch) | |
tree | 537cf3fba82d5d7e438f930a428b564c8d6b6e8e /arch | |
parent | 1b60280834683dddf4975bbf9662a74f123ba770 (diff) | |
download | linux-6dc2a774cb4fdb524b7eb0b8db74198a1b4815ea.tar.xz |
x86/Hyper-V: Support for free page reporting
Linux has support for free page reporting now (36e66c554b5c) for
virtualized environment. On Hyper-V when virtually backed VMs are
configured, Hyper-V will advertise cold memory discard capability,
when supported. This patch adds the support to hook into the free
page reporting infrastructure and leverage the Hyper-V cold memory
discard hint hypercall to report/free these pages back to the host.
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Tested-by: Matheus Castello <matheus@castello.eng.br>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/SN4PR2101MB0880121FA4E2FEC67F35C1DCC0649@SN4PR2101MB0880.namprd21.prod.outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/hyperv/hv_init.c | 51 | ||||
-rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 9 |
2 files changed, 55 insertions, 5 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 9d100257b3af..7c9da3f65afa 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -498,6 +498,8 @@ void __init hyperv_init(void) x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain; #endif + /* Query the VMs extended capability once, so that it can be cached. */ + hv_query_ext_cap(0); return; remove_cpuhp_state: @@ -601,7 +603,7 @@ EXPORT_SYMBOL_GPL(hv_is_hibernation_supported); enum hv_isolation_type hv_get_isolation_type(void) { - if (!(ms_hyperv.features_b & HV_ISOLATION)) + if (!(ms_hyperv.priv_high & HV_ISOLATION)) return HV_ISOLATION_TYPE_NONE; return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b); } @@ -612,3 +614,50 @@ bool hv_is_isolation_supported(void) return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; } EXPORT_SYMBOL_GPL(hv_is_isolation_supported); + +/* Bit mask of the extended capability to query: see HV_EXT_CAPABILITY_xxx */ +bool hv_query_ext_cap(u64 cap_query) +{ + /* + * The address of the 'hv_extended_cap' variable will be used as an + * output parameter to the hypercall below and so it should be + * compatible with 'virt_to_phys'. Which means, it's address should be + * directly mapped. Use 'static' to keep it compatible; stack variables + * can be virtually mapped, making them imcompatible with + * 'virt_to_phys'. + * Hypercall input/output addresses should also be 8-byte aligned. + */ + static u64 hv_extended_cap __aligned(8); + static bool hv_extended_cap_queried; + u64 status; + + /* + * Querying extended capabilities is an extended hypercall. Check if the + * partition supports extended hypercall, first. + */ + if (!(ms_hyperv.priv_high & HV_ENABLE_EXTENDED_HYPERCALLS)) + return false; + + /* Extended capabilities do not change at runtime. */ + if (hv_extended_cap_queried) + return hv_extended_cap & cap_query; + + status = hv_do_hypercall(HV_EXT_CALL_QUERY_CAPABILITIES, NULL, + &hv_extended_cap); + + /* + * The query extended capabilities hypercall should not fail under + * any normal circumstances. Avoid repeatedly making the hypercall, on + * error. + */ + hv_extended_cap_queried = true; + status &= HV_HYPERCALL_RESULT_MASK; + if (status != HV_STATUS_SUCCESS) { + pr_err("Hyper-V: Extended query capabilities hypercall failed 0x%llx\n", + status); + return false; + } + + return hv_extended_cap & cap_query; +} +EXPORT_SYMBOL_GPL(hv_query_ext_cap); diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index cebed535ec56..3546d3e21787 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -265,12 +265,13 @@ static void __init ms_hyperv_init_platform(void) * Extract the features and hints */ ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); - ms_hyperv.features_b = cpuid_ebx(HYPERV_CPUID_FEATURES); + ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES); ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); - pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n", - ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features); + pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n", + ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints, + ms_hyperv.misc_features); ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); @@ -316,7 +317,7 @@ static void __init ms_hyperv_init_platform(void) x86_platform.calibrate_cpu = hv_get_tsc_khz; } - if (ms_hyperv.features_b & HV_ISOLATION) { + if (ms_hyperv.priv_high & HV_ISOLATION) { ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG); ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG); |