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| author | Saurabh Sengar <ssengar@linux.microsoft.com> | 2023-09-20 06:04:35 +0200 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2023-09-22 20:40:53 +0200 |
| commit | f2a55d08d7e1a5746dad80fc5eda023eff2eeea5 (patch) | |
| tree | 1accc73c8ee6d950c7e9a6370112c8cc5e3cf8bb /arch/x86/hyperv | |
| parent | Linux 6.6-rc2 (diff) | |
| download | linux-f2a55d08d7e1a5746dad80fc5eda023eff2eeea5.tar.xz linux-f2a55d08d7e1a5746dad80fc5eda023eff2eeea5.zip | |
x86/hyperv: Restrict get_vtl to only VTL platforms
When Linux runs in a non-default VTL (CONFIG_HYPERV_VTL_MODE=y),
get_vtl() must never fail as its return value is used in negotiations
with the host. In the more generic case, (CONFIG_HYPERV_VTL_MODE=n) the
VTL is always zero so there's no need to do the hypercall.
Make get_vtl() BUG() in case of failure and put the implementation under
"if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)" to avoid the call altogether in
the most generic use case.
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/1695182675-13405-1-git-send-email-ssengar@linux.microsoft.com
Diffstat (limited to 'arch/x86/hyperv')
| -rw-r--r-- | arch/x86/hyperv/hv_init.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 783ed339f341..f0128fd4031d 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -394,6 +394,7 @@ static void __init hv_get_partition_id(void) local_irq_restore(flags); } +#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE) static u8 __init get_vtl(void) { u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS; @@ -416,13 +417,16 @@ static u8 __init get_vtl(void) if (hv_result_success(ret)) { ret = output->as64.low & HV_X64_VTL_MASK; } else { - pr_err("Failed to get VTL(%lld) and set VTL to zero by default.\n", ret); - ret = 0; + pr_err("Failed to get VTL(error: %lld) exiting...\n", ret); + BUG(); } local_irq_restore(flags); return ret; } +#else +static inline u8 get_vtl(void) { return 0; } +#endif /* * This function is to be invoked early in the boot sequence after the @@ -604,8 +608,7 @@ skip_hypercall_pg_init: hv_query_ext_cap(0); /* Find the VTL */ - if (!ms_hyperv.paravisor_present && hv_isolation_type_snp()) - ms_hyperv.vtl = get_vtl(); + ms_hyperv.vtl = get_vtl(); return; |