diff options
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/x86/drivers/hyperv/hyperv.c | 135 |
1 files changed, 125 insertions, 10 deletions
diff --git a/src/arch/x86/drivers/hyperv/hyperv.c b/src/arch/x86/drivers/hyperv/hyperv.c index b90937df..98c2b30c 100644 --- a/src/arch/x86/drivers/hyperv/hyperv.c +++ b/src/arch/x86/drivers/hyperv/hyperv.c @@ -40,6 +40,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include <ipxe/malloc.h> #include <ipxe/device.h> #include <ipxe/timer.h> +#include <ipxe/quiesce.h> #include <ipxe/cpuid.h> #include <ipxe/msr.h> #include <ipxe/hyperv.h> @@ -299,6 +300,10 @@ static void hv_map_synic ( struct hv_hypervisor *hv ) { uint64_t siefp; uint64_t scontrol; + /* Zero SynIC message and event pages */ + memset ( hv->synic.message, 0, PAGE_SIZE ); + memset ( hv->synic.event, 0, PAGE_SIZE ); + /* Map SynIC message page */ simp = rdmsr ( HV_X64_MSR_SIMP ); simp &= ( PAGE_SIZE - 1 ); @@ -321,21 +326,14 @@ static void hv_map_synic ( struct hv_hypervisor *hv ) { } /** - * Unmap synthetic interrupt controller + * Unmap synthetic interrupt controller, leaving SCONTROL untouched * * @v hv Hyper-V hypervisor */ -static void hv_unmap_synic ( struct hv_hypervisor *hv ) { - uint64_t scontrol; +static void hv_unmap_synic_no_scontrol ( struct hv_hypervisor *hv ) { uint64_t siefp; uint64_t simp; - /* Disable SynIC */ - scontrol = rdmsr ( HV_X64_MSR_SCONTROL ); - scontrol &= ~HV_SCONTROL_ENABLE; - DBGC2 ( hv, "HV %p SCONTROL MSR is %#08llx\n", hv, scontrol ); - wrmsr ( HV_X64_MSR_SCONTROL, scontrol ); - /* Unmap SynIC event page */ siefp = rdmsr ( HV_X64_MSR_SIEFP ); siefp &= ( ( PAGE_SIZE - 1 ) & ~HV_SIEFP_ENABLE ); @@ -350,6 +348,24 @@ static void hv_unmap_synic ( struct hv_hypervisor *hv ) { } /** + * Unmap synthetic interrupt controller + * + * @v hv Hyper-V hypervisor + */ +static void hv_unmap_synic ( struct hv_hypervisor *hv ) { + uint64_t scontrol; + + /* Disable SynIC */ + scontrol = rdmsr ( HV_X64_MSR_SCONTROL ); + scontrol &= ~HV_SCONTROL_ENABLE; + DBGC2 ( hv, "HV %p SCONTROL MSR is %#08llx\n", hv, scontrol ); + wrmsr ( HV_X64_MSR_SCONTROL, scontrol ); + + /* Unmap SynIC event and message pages */ + hv_unmap_synic_no_scontrol ( hv ); +} + +/** * Enable synthetic interrupt * * @v hv Hyper-V hypervisor @@ -385,8 +401,12 @@ void hv_disable_sint ( struct hv_hypervisor *hv, unsigned int sintx ) { unsigned long msr = HV_X64_MSR_SINT ( sintx ); uint64_t sint; - /* Disable synthetic interrupt */ + /* Do nothing if interrupt is already disabled */ sint = rdmsr ( msr ); + if ( sint & HV_SINT_MASKED ) + return; + + /* Disable synthetic interrupt */ sint &= ~HV_SINT_AUTO_EOI; sint |= HV_SINT_MASKED; DBGC2 ( hv, "HV %p SINT%d MSR is %#08llx\n", hv, sintx, sint ); @@ -589,6 +609,7 @@ static void hv_remove ( struct root_device *rootdev ) { hv_free_pages ( hv, hv->hypercall, hv->synic.message, hv->synic.event, NULL ); free ( hv ); + rootdev_set_drvdata ( rootdev, NULL ); } /** Hyper-V root device driver */ @@ -604,6 +625,100 @@ struct root_device hv_root_device __root_device = { }; /** + * Quiesce system + * + */ +static void hv_quiesce ( void ) { + struct hv_hypervisor *hv = rootdev_get_drvdata ( &hv_root_device ); + unsigned int i; + + /* Do nothing if we are not running in Hyper-V */ + if ( ! hv ) + return; + + /* The "enlightened" portions of the Windows Server 2016 boot + * process will not cleanly take ownership of an active + * Hyper-V connection. Experimentation shows that the minimum + * requirement is that we disable the SynIC message page + * (i.e. zero the SIMP MSR). + * + * We cannot perform a full shutdown of the Hyper-V + * connection. Experimentation shows that if we disable the + * SynIC (i.e. zero the SCONTROL MSR) then Windows Server 2016 + * will enter an indefinite wait loop. + * + * Attempt to create a safe handover environment by resetting + * all MSRs except for SCONTROL. + * + * Note that we do not shut down our VMBus devices, since we + * may need to unquiesce the system and continue operation. + */ + + /* Disable all synthetic interrupts */ + for ( i = 0 ; i <= HV_SINT_MAX ; i++ ) + hv_disable_sint ( hv, i ); + + /* Unmap synthetic interrupt controller, leaving SCONTROL + * enabled (see above). + */ + hv_unmap_synic_no_scontrol ( hv ); + + /* Unmap hypercall page */ + hv_unmap_hypercall ( hv ); + + DBGC ( hv, "HV %p quiesced\n", hv ); +} + +/** + * Unquiesce system + * + */ +static void hv_unquiesce ( void ) { + struct hv_hypervisor *hv = rootdev_get_drvdata ( &hv_root_device ); + uint64_t simp; + int rc; + + /* Do nothing if we are not running in Hyper-V */ + if ( ! hv ) + return; + + /* Experimentation shows that the "enlightened" portions of + * Windows Server 2016 will break our Hyper-V connection at + * some point during a SAN boot. Surprisingly it does not + * change the guest OS ID MSR, but it does leave the SynIC + * message page disabled. + * + * Our own explicit quiescing procedure will also disable the + * SynIC message page. We can therefore use the SynIC message + * page enable bit as a heuristic to determine when we need to + * reestablish our Hyper-V connection. + */ + simp = rdmsr ( HV_X64_MSR_SIMP ); + if ( simp & HV_SIMP_ENABLE ) + return; + + /* Remap hypercall page */ + hv_map_hypercall ( hv ); + + /* Remap synthetic interrupt controller */ + hv_map_synic ( hv ); + + /* Reset Hyper-V devices */ + if ( ( rc = vmbus_reset ( hv, &hv_root_device.dev ) ) != 0 ) { + DBGC ( hv, "HV %p could not unquiesce: %s\n", + hv, strerror ( rc ) ); + /* Nothing we can do */ + return; + } +} + +/** Hyper-V quiescer */ +struct quiescer hv_quiescer __quiescer = { + .quiesce = hv_quiesce, + .unquiesce = hv_unquiesce, +}; + +/** * Probe timer * * @ret rc Return status code |