Messages in this thread | | | Date | Wed, 3 Apr 2024 16:08:35 -0500 | Subject | Re: [PATCH] x86/sev: Apply RMP table fixups for kexec. | From | "Kalra, Ashish" <> |
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On 4/2/2024 5:42 PM, Michael Roth wrote: > On Tue, Apr 02, 2024 at 05:31:09PM -0500, Kalra, Ashish wrote: >> On 4/2/2024 5:09 PM, Tom Lendacky wrote: >>> On 3/12/24 13:47, Ashish Kalra wrote: >>>> From: Ashish Kalra <ashish.kalra@amd.com> >>>> >>>> RMP table start and end physical range may not be aligned to 2MB in >>>> the e820 tables causing fatal RMP page faults during kexec boot when >>>> new page allocations are done in the same 2MB page as the RMP table. >>>> Check if RMP table start and end physical range in e820_table is not >>>> aligned to 2MB and in that case use e820__range_update() to map this >>>> range to reserved. >>>> >>>> Override e820__memory_setup_default() to check and apply these RMP table >>>> fixups in e820_table before e820_table is used to setup >>>> e280_table_firmware and e820_table_kexec. >>>> >>>> Fixes: c3b86e61b756 ("x86/cpufeatures: Enable/unmask SEV-SNP CPU >>>> feature") >>>> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> >>>> --- >>>> arch/x86/virt/svm/sev.c | 52 +++++++++++++++++++++++++++++++++++++++++ >>>> 1 file changed, 52 insertions(+) >>>> >>>> diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c >>>> index cffe1157a90a..e0d7584df28f 100644 >>>> --- a/arch/x86/virt/svm/sev.c >>>> +++ b/arch/x86/virt/svm/sev.c >>>> @@ -65,6 +65,8 @@ static u64 probed_rmp_base, probed_rmp_size; >>>> static struct rmpentry *rmptable __ro_after_init; >>>> static u64 rmptable_max_pfn __ro_after_init; >>>> +static char *__init snp_rmptable_e820_fixup(void); >>>> + >>>> static LIST_HEAD(snp_leaked_pages_list); >>>> static DEFINE_SPINLOCK(snp_leaked_pages_list_lock); >>>> @@ -160,9 +162,59 @@ bool snp_probe_rmptable_info(void) >>>> pr_info("RMP table physical range [0x%016llx - 0x%016llx]\n", >>>> probed_rmp_base, probed_rmp_base + probed_rmp_size - 1); >>>> + /* >>>> + * Override e820__memory_setup_default() to do any RMP table fixups >>>> + * for kexec if required. >>>> + */ >>>> + x86_init.resources.memory_setup = snp_rmptable_e820_fixup; >>> This produces a build warning: >>> >>> WARNING: modpost: vmlinux: section mismatch in reference: >>> snp_probe_rmptable_info+0x95 (section: .text) -> x86_init (section: >>> .init.data) >>> WARNING: modpost: vmlinux: section mismatch in reference: >>> snp_probe_rmptable_info+0x99 (section: .text) -> snp_rmptable_e820_fixup >>> (section: .init.text) >>> >> Oh, so this requires snp_probe_rmptable_info() to be fixed to use the __init >> macro. >> >> I believe that snp_probe_rmptable_info() should be anyway using the __init >> macro and this fix for snp_probe_rmptable_info() needs to be sent as a >> separate patch and regardless of this patch getting merged or not. > I think you'll hit issues with: > > bsp_determine_snp() -> //non-__init > snp_probe_rmptable_info() //__init > > and bsp_determine_snp() sticks around as a function pointer assigned to > cpuinfo_x86 so I don't think you can use __init there. > > So might need to just drop __init from snp_rmptable_e820_fixup().
Actually, that will not help as snp_probe_rmptable_info() is *also* accessing x86_init.resources.memory_setup
Thanks, Ashish
> >> Thanks, Ashish >> >>> Thanks, >>> Tom >>> >>>> + >>>> return true; >>>> }
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