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Date:   Fri, 3 Nov 2017 10:31:20 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Tomeu Vizoso <tomeu@...euvizoso.net>
Cc:     x86@...nel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-arch@...r.kernel.org, linux-efi@...r.kernel.org,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        linux-mm@...ck.org, kvm@...r.kernel.org,
        kasan-dev@...glegroups.com,
        Radim Krčmář <rkrcmar@...hat.com>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Alexander Potapenko <glider@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Rik van Riel <riel@...hat.com>,
        Larry Woodman <lwoodman@...hat.com>,
        Dave Young <dyoung@...hat.com>,
        Toshimitsu Kani <toshi.kani@....com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Guenter Roeck <groeck@...gle.com>,
        Zach Reizner <zachr@...gle.com>,
        Dylan Reid <dgreid@...omium.org>
Subject: Re: [PATCH v10 20/38] x86, mpparse: Use memremap to map the mpf and
 mpc data

On 11/3/2017 10:12 AM, Tomeu Vizoso wrote:
> On 17 July 2017 at 23:10, Tom Lendacky <thomas.lendacky@....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@...e.de>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@....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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