Messages in this thread | | | Date | Wed, 13 Mar 2024 16:28:37 +0530 | Subject | Re: [PATCH] x86/sev: Apply RMP table fixups for kexec. | From | "Aithal, Srikanth" <> |
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On 3/13/2024 12:17 AM, 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; > + > return true; > } > > +/* > + * Override e820__memory_setup_default() to do any RMP table fixups > + * in e820_table before e820_table_firmware and e820_table_kexec > + * are setup. > + */ > +static char *__init snp_rmptable_e820_fixup(void) > +{ > + /* Populate e820_table from BIOS-supplied e820 map */ > + char *p = e820__memory_setup_default(); > + u64 pa; > + > + /* > + * RMP table start & 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 & 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, > + * e820__range_update() nicely handles partial range update and also > + * merges any consecutive ranges of the same type. > + * Need to override e820__memory_setup_default() to check and apply > + * fixups in e820_table before e820_table is used to setup > + * e280_table_firmware and e820_table_kexec. > + */ > + pa = probed_rmp_base; > + if (!IS_ALIGNED(pa, PMD_SIZE)) { > + pa = ALIGN_DOWN(pa, PMD_SIZE); > + if (e820__mapped_any(pa, pa + PMD_SIZE, E820_TYPE_RAM)) { > + pr_info("Reserving start of RMP table on a 2MB boundary [0x%016llx]\n", pa); > + e820__range_update(pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED); > + } > + } > + > + pa = probed_rmp_base + probed_rmp_size; > + if (!IS_ALIGNED(pa, PMD_SIZE)) { > + pa = ALIGN_DOWN(pa, PMD_SIZE); > + if (e820__mapped_any(pa, pa + PMD_SIZE, E820_TYPE_RAM)) { > + pr_info("Reserving end of RMP table on a 2MB boundary [0x%016llx]\n", pa); > + e820__range_update(pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED); > + } > + } > + > + return p; > +} > + > /* > * Do the necessary preparations which are verified by the firmware as > * described in the SNP_INIT_EX firmware command description in the SNP Tested this patch, it fixes the kexec issue reported. Thank you.
Tested-by: Srikanth Aithal <sraithal@amd.com>
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