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SubjectRe: [PATCH v10 20/38] x86, mpparse: Use memremap to map the mpf and mpc data
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On 11/3/2017 10:12 AM, Tomeu Vizoso wrote:
> On 17 July 2017 at 23:10, Tom Lendacky <thomas.lendacky@amd.com> wrote:
>> The SMP MP-table is built by UEFI and placed in memory in a decrypted
>> state. These tables are accessed using a mix of early_memremap(),
>> early_memunmap(), phys_to_virt() and virt_to_phys(). Change all accesses
>> to use early_memremap()/early_memunmap(). This allows for proper setting
>> of the encryption mask so that the data can be successfully accessed when
>> SME is active.
>>
>> Reviewed-by: Borislav Petkov <bp@suse.de>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>> arch/x86/kernel/mpparse.c | 98 +++++++++++++++++++++++++++++++++--------------
>> 1 file changed, 70 insertions(+), 28 deletions(-)
>
> Hi there,
>
> today I played a bit with crosvm [0] and noticed that 4.14-rc7 doesn't
> boot. git-bisect pointed to this patch, and reverting it indeed gets
> things working again.
>
> Anybody has an idea of why this could be?

If you send me your kernel config I'll see if I can reproduce the issue
and debug it.

Thanks,
Tom

>
> Thanks,
>
> Tomeu
>
> [0] https://chromium.googlesource.com/chromiumos/platform/crosvm
>
>>
>> diff --git a/arch/x86/kernel/mpparse.c b/arch/x86/kernel/mpparse.c
>> index fd37f39..5cbb317 100644
>> --- a/arch/x86/kernel/mpparse.c
>> +++ b/arch/x86/kernel/mpparse.c
>> @@ -429,7 +429,7 @@ static inline void __init construct_default_ISA_mptable(int mpc_default_type)
>> }
>> }
>>
>> -static struct mpf_intel *mpf_found;
>> +static unsigned long mpf_base;
>>
>> static unsigned long __init get_mpc_size(unsigned long physptr)
>> {
>> @@ -451,6 +451,7 @@ static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
>>
>> size = get_mpc_size(mpf->physptr);
>> mpc = early_memremap(mpf->physptr, size);
>> +
>> /*
>> * Read the physical hardware table. Anything here will
>> * override the defaults.
>> @@ -497,12 +498,12 @@ static int __init check_physptr(struct mpf_intel *mpf, unsigned int early)
>> */
>> void __init default_get_smp_config(unsigned int early)
>> {
>> - struct mpf_intel *mpf = mpf_found;
>> + struct mpf_intel *mpf;
>>
>> if (!smp_found_config)
>> return;
>>
>> - if (!mpf)
>> + if (!mpf_base)
>> return;
>>
>> if (acpi_lapic && early)
>> @@ -515,6 +516,12 @@ void __init default_get_smp_config(unsigned int early)
>> if (acpi_lapic && acpi_ioapic)
>> return;
>>
>> + mpf = early_memremap(mpf_base, sizeof(*mpf));
>> + if (!mpf) {
>> + pr_err("MPTABLE: error mapping MP table\n");
>> + return;
>> + }
>> +
>> pr_info("Intel MultiProcessor Specification v1.%d\n",
>> mpf->specification);
>> #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_32)
>> @@ -529,7 +536,7 @@ void __init default_get_smp_config(unsigned int early)
>> /*
>> * Now see if we need to read further.
>> */
>> - if (mpf->feature1 != 0) {
>> + if (mpf->feature1) {
>> if (early) {
>> /*
>> * local APIC has default address
>> @@ -542,8 +549,10 @@ void __init default_get_smp_config(unsigned int early)
>> construct_default_ISA_mptable(mpf->feature1);
>>
>> } else if (mpf->physptr) {
>> - if (check_physptr(mpf, early))
>> + if (check_physptr(mpf, early)) {
>> + early_memunmap(mpf, sizeof(*mpf));
>> return;
>> + }
>> } else
>> BUG();
>>
>> @@ -552,6 +561,8 @@ void __init default_get_smp_config(unsigned int early)
>> /*
>> * Only use the first configuration found.
>> */
>> +
>> + early_memunmap(mpf, sizeof(*mpf));
>> }
>>
>> static void __init smp_reserve_memory(struct mpf_intel *mpf)
>> @@ -561,15 +572,16 @@ static void __init smp_reserve_memory(struct mpf_intel *mpf)
>>
>> static int __init smp_scan_config(unsigned long base, unsigned long length)
>> {
>> - unsigned int *bp = phys_to_virt(base);
>> + unsigned int *bp;
>> struct mpf_intel *mpf;
>> - unsigned long mem;
>> + int ret = 0;
>>
>> apic_printk(APIC_VERBOSE, "Scan for SMP in [mem %#010lx-%#010lx]\n",
>> base, base + length - 1);
>> BUILD_BUG_ON(sizeof(*mpf) != 16);
>>
>> while (length > 0) {
>> + bp = early_memremap(base, length);
>> mpf = (struct mpf_intel *)bp;
>> if ((*bp == SMP_MAGIC_IDENT) &&
>> (mpf->length == 1) &&
>> @@ -579,24 +591,26 @@ static int __init smp_scan_config(unsigned long base, unsigned long length)
>> #ifdef CONFIG_X86_LOCAL_APIC
>> smp_found_config = 1;
>> #endif
>> - mpf_found = mpf;
>> + mpf_base = base;
>>
>> - pr_info("found SMP MP-table at [mem %#010llx-%#010llx] mapped at [%p]\n",
>> - (unsigned long long) virt_to_phys(mpf),
>> - (unsigned long long) virt_to_phys(mpf) +
>> - sizeof(*mpf) - 1, mpf);
>> + pr_info("found SMP MP-table at [mem %#010lx-%#010lx] mapped at [%p]\n",
>> + base, base + sizeof(*mpf) - 1, mpf);
>>
>> - mem = virt_to_phys(mpf);
>> - memblock_reserve(mem, sizeof(*mpf));
>> + memblock_reserve(base, sizeof(*mpf));
>> if (mpf->physptr)
>> smp_reserve_memory(mpf);
>>
>> - return 1;
>> + ret = 1;
>> }
>> - bp += 4;
>> + early_memunmap(bp, length);
>> +
>> + if (ret)
>> + break;
>> +
>> + base += 16;
>> length -= 16;
>> }
>> - return 0;
>> + return ret;
>> }
>>
>> void __init default_find_smp_config(void)
>> @@ -838,29 +852,40 @@ static int __init update_mp_table(void)
>> char oem[10];
>> struct mpf_intel *mpf;
>> struct mpc_table *mpc, *mpc_new;
>> + unsigned long size;
>>
>> if (!enable_update_mptable)
>> return 0;
>>
>> - mpf = mpf_found;
>> - if (!mpf)
>> + if (!mpf_base)
>> + return 0;
>> +
>> + mpf = early_memremap(mpf_base, sizeof(*mpf));
>> + if (!mpf) {
>> + pr_err("MPTABLE: mpf early_memremap() failed\n");
>> return 0;
>> + }
>>
>> /*
>> * Now see if we need to go further.
>> */
>> - if (mpf->feature1 != 0)
>> - return 0;
>> + if (mpf->feature1)
>> + goto do_unmap_mpf;
>>
>> if (!mpf->physptr)
>> - return 0;
>> + goto do_unmap_mpf;
>>
>> - mpc = phys_to_virt(mpf->physptr);
>> + size = get_mpc_size(mpf->physptr);
>> + mpc = early_memremap(mpf->physptr, size);
>> + if (!mpc) {
>> + pr_err("MPTABLE: mpc early_memremap() failed\n");
>> + goto do_unmap_mpf;
>> + }
>>
>> if (!smp_check_mpc(mpc, oem, str))
>> - return 0;
>> + goto do_unmap_mpc;
>>
>> - pr_info("mpf: %llx\n", (u64)virt_to_phys(mpf));
>> + pr_info("mpf: %llx\n", (u64)mpf_base);
>> pr_info("physptr: %x\n", mpf->physptr);
>>
>> if (mpc_new_phys && mpc->length > mpc_new_length) {
>> @@ -878,21 +903,32 @@ static int __init update_mp_table(void)
>> new = mpf_checksum((unsigned char *)mpc, mpc->length);
>> if (old == new) {
>> pr_info("mpc is readonly, please try alloc_mptable instead\n");
>> - return 0;
>> + goto do_unmap_mpc;
>> }
>> pr_info("use in-position replacing\n");
>> } else {
>> + mpc_new = early_memremap(mpc_new_phys, mpc_new_length);
>> + if (!mpc_new) {
>> + pr_err("MPTABLE: new mpc early_memremap() failed\n");
>> + goto do_unmap_mpc;
>> + }
>> mpf->physptr = mpc_new_phys;
>> - mpc_new = phys_to_virt(mpc_new_phys);
>> memcpy(mpc_new, mpc, mpc->length);
>> + early_memunmap(mpc, size);
>> mpc = mpc_new;
>> + size = mpc_new_length;
>> /* check if we can modify that */
>> if (mpc_new_phys - mpf->physptr) {
>> struct mpf_intel *mpf_new;
>> /* steal 16 bytes from [0, 1k) */
>> + mpf_new = early_memremap(0x400 - 16, sizeof(*mpf_new));
>> + if (!mpf_new) {
>> + pr_err("MPTABLE: new mpf early_memremap() failed\n");
>> + goto do_unmap_mpc;
>> + }
>> pr_info("mpf new: %x\n", 0x400 - 16);
>> - mpf_new = phys_to_virt(0x400 - 16);
>> memcpy(mpf_new, mpf, 16);
>> + early_memunmap(mpf, sizeof(*mpf));
>> mpf = mpf_new;
>> mpf->physptr = mpc_new_phys;
>> }
>> @@ -909,6 +945,12 @@ static int __init update_mp_table(void)
>> */
>> replace_intsrc_all(mpc, mpc_new_phys, mpc_new_length);
>>
>> +do_unmap_mpc:
>> + early_memunmap(mpc, size);
>> +
>> +do_unmap_mpf:
>> + early_memunmap(mpf, sizeof(*mpf));
>> +
>> return 0;
>> }
>>
>> --
>> 1.9.1
>>

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