From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
Sean Christopherson <seanjc@google.com>,
linux-kernel@vger.kernel.org,
Kai Huang <kai.huang@linux.intel.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: Re: [RFC v1 25/26] x86/tdx: Make DMA pages shared
Date: Tue, 6 Apr 2021 19:31:50 +0300 [thread overview]
Message-ID: <20210406163150.cbmcybnu6hu5alk7@box> (raw)
In-Reply-To: <cc8e2e73-9d08-894c-47f9-ec82b0642789@intel.com>
On Thu, Apr 01, 2021 at 02:01:15PM -0700, Dave Hansen wrote:
> > +int tdx_map_gpa(phys_addr_t gpa, int numpages, bool private)
> > +{
> > + int ret, i;
> > +
> > + ret = __tdx_map_gpa(gpa, numpages, private);
> > + if (ret || !private)
> > + return ret;
> > +
> > + for (i = 0; i < numpages; i++)
> > + tdx_accept_page(gpa + i*PAGE_SIZE);
> > +
> > + return 0;
> > +}
>
> Please do something like this:
>
> enum tdx_max_type {
> TDX_MAP_PRIVATE,
> TDX_MAP_SHARED
> }
>
> Then, your calls will look like:
>
> tdx_map_gpa(gpa, nr, TDX_MAP_SHARED);
>
> instead of:
>
> tdx_map_gpa(gpa, nr, false);
Okay, makes sense.
> > static __cpuidle void tdx_halt(void)
> > {
> > register long r10 asm("r10") = TDVMCALL_STANDARD;
> > diff --git a/arch/x86/mm/mem_encrypt_common.c b/arch/x86/mm/mem_encrypt_common.c
> > index 964e04152417..b6d93b0c5dcf 100644
> > --- a/arch/x86/mm/mem_encrypt_common.c
> > +++ b/arch/x86/mm/mem_encrypt_common.c
> > @@ -15,9 +15,9 @@
> > bool force_dma_unencrypted(struct device *dev)
> > {
> > /*
> > - * For SEV, all DMA must be to unencrypted/shared addresses.
> > + * For SEV and TDX, all DMA must be to unencrypted/shared addresses.
> > */
> > - if (sev_active())
> > + if (sev_active() || is_tdx_guest())
> > return true;
> >
> > /*
> > diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
> > index 16f878c26667..6f23a9816ef0 100644
> > --- a/arch/x86/mm/pat/set_memory.c
> > +++ b/arch/x86/mm/pat/set_memory.c
> > @@ -27,6 +27,7 @@
> > #include <asm/proto.h>
> > #include <asm/memtype.h>
> > #include <asm/set_memory.h>
> > +#include <asm/tdx.h>
> >
> > #include "../mm_internal.h"
> >
> > @@ -1977,8 +1978,8 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> > struct cpa_data cpa;
> > int ret;
> >
> > - /* Nothing to do if memory encryption is not active */
> > - if (!mem_encrypt_active())
> > + /* Nothing to do if memory encryption and TDX are not active */
> > + if (!mem_encrypt_active() && !is_tdx_guest())
> > return 0;
>
> So, this is starting to look like the "enc" naming is wrong, or at least
> a little misleading. Should we be talking about "protection" or
> "guards" or something?
Are you talking about the function argument or function name too?
> > /* Should not be working on unaligned addresses */
> > @@ -1988,8 +1989,14 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> > memset(&cpa, 0, sizeof(cpa));
> > cpa.vaddr = &addr;
> > cpa.numpages = numpages;
> > - cpa.mask_set = enc ? __pgprot(_PAGE_ENC) : __pgprot(0);
> > - cpa.mask_clr = enc ? __pgprot(0) : __pgprot(_PAGE_ENC);
> > + if (is_tdx_guest()) {
> > + cpa.mask_set = __pgprot(enc ? 0 : tdx_shared_mask());
> > + cpa.mask_clr = __pgprot(enc ? tdx_shared_mask() : 0);
> > + } else {
> > + cpa.mask_set = __pgprot(enc ? _PAGE_ENC : 0);
> > + cpa.mask_clr = __pgprot(enc ? 0 : _PAGE_ENC);
> > + }
>
> OK, this is too hideous to live. It sucks that the TDX and SEV/SME bits
> are opposite polarity, but oh well.
>
> To me, this gets a lot clearer, and opens up room for commenting if you
> do something like:
>
> if (is_tdx_guest()) {
> mem_enc_bits = 0;
> mem_plain_bits = tdx_shared_mask();
> } else {
> mem_enc_bits = _PAGE_ENC;
> mem_plain_bits = 0
> }
>
> if (enc) {
> cpa.mask_set = mem_enc_bits;
> cpa.mask_clr = mem_plain_bits; // clear "plain" bits
> } else {
>
> cpa.mask_set = mem_plain_bits;
> cpa.mask_clr = mem_enc_bits; // clear encryption bits
> }
I'm not convinced that your approach it clearer. If you add the missing
__pgprot() it going to as ugly as the original.
But if a maintainer wants... :)
> > cpa.pgd = init_mm.pgd;
> >
> > /* Must avoid aliasing mappings in the highmem code */
> > @@ -1999,7 +2006,8 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> > /*
> > * Before changing the encryption attribute, we need to flush caches.
> > */
> > - cpa_flush(&cpa, !this_cpu_has(X86_FEATURE_SME_COHERENT));
> > + if (!enc || !is_tdx_guest())
> > + cpa_flush(&cpa, !this_cpu_has(X86_FEATURE_SME_COHERENT));
>
> That "!enc" looks wrong to me. Caches would need to be flushed whenever
> encryption attributes *change*, not just when they are set.
>
> Also, cpa_flush() flushes caches *AND* the TLB. How does TDX manage to
> not need TLB flushes?
I will double-check everthing, but I think we can skip *both* cpa_flush()
for private->shared conversion. VMM and TDX module will take care about
TLB and cache flush in response to MapGPA TDVMCALL.
> > ret = __change_page_attr_set_clr(&cpa, 1);
> >
> > @@ -2012,6 +2020,11 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> > */
> > cpa_flush(&cpa, 0);
> >
> > + if (!ret && is_tdx_guest()) {
> > + ret = tdx_map_gpa(__pa(addr), numpages, enc);
> > + // XXX: need to undo on error?
> > + }
>
> Time to fix this stuff up if you want folks to take this series more
> seriously.
My bad, will fix it.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-04-06 16:31 UTC|newest]
Thread overview: 161+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-06 3:02 Test Email sathyanarayanan.kuppuswamy
2021-02-05 23:38 ` [RFC v1 00/26] Add TDX Guest Support Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 01/26] x86/paravirt: Introduce CONFIG_PARAVIRT_XL Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 02/26] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 03/26] x86/cpufeatures: Add is_tdx_guest() interface Kuppuswamy Sathyanarayanan
2021-04-01 21:08 ` Dave Hansen
2021-04-01 21:15 ` Kuppuswamy, Sathyanarayanan
2021-04-01 21:19 ` Dave Hansen
2021-04-01 22:25 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 04/26] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-02-08 10:00 ` Peter Zijlstra
2021-02-08 19:10 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 05/26] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-02-08 10:20 ` Peter Zijlstra
2021-02-08 16:23 ` Andi Kleen
2021-02-08 16:33 ` Peter Zijlstra
2021-02-08 16:46 ` Sean Christopherson
2021-02-08 16:59 ` Peter Zijlstra
2021-02-08 19:05 ` Kuppuswamy, Sathyanarayanan
2021-02-08 16:46 ` Andi Kleen
2021-02-12 19:20 ` Dave Hansen
2021-02-12 19:47 ` Andy Lutomirski
2021-02-12 20:06 ` Sean Christopherson
2021-02-12 20:17 ` Dave Hansen
2021-02-12 20:37 ` Sean Christopherson
2021-02-12 20:46 ` Dave Hansen
2021-02-12 20:54 ` Sean Christopherson
2021-02-12 21:06 ` Dave Hansen
2021-02-12 21:37 ` Sean Christopherson
2021-02-12 21:47 ` Andy Lutomirski
2021-02-12 21:48 ` Dave Hansen
2021-02-14 19:33 ` Andi Kleen
2021-02-14 19:54 ` Andy Lutomirski
2021-02-12 20:20 ` Andy Lutomirski
2021-02-12 20:44 ` Sean Christopherson
2021-02-05 23:38 ` [RFC v1 06/26] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 07/26] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 08/26] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 09/26] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-02-05 23:42 ` Andy Lutomirski
2021-02-07 14:13 ` Kirill A. Shutemov
2021-02-07 16:01 ` Dave Hansen
2021-02-07 20:29 ` Kirill A. Shutemov
2021-02-07 22:31 ` Dave Hansen
2021-02-07 22:45 ` Andy Lutomirski
2021-02-08 17:10 ` Sean Christopherson
2021-02-08 17:35 ` Andy Lutomirski
2021-02-08 17:47 ` Sean Christopherson
2021-03-18 21:30 ` [PATCH v1 1/1] x86/tdx: Add tdcall() and tdvmcall() helper functions Kuppuswamy Sathyanarayanan
2021-03-19 16:55 ` Sean Christopherson
2021-03-19 17:42 ` Kuppuswamy, Sathyanarayanan
2021-03-19 18:22 ` Dave Hansen
2021-03-19 19:58 ` Kuppuswamy, Sathyanarayanan
2021-03-26 23:38 ` [PATCH v2 1/1] x86/tdx: Add __tdcall() and __tdvmcall() " Kuppuswamy Sathyanarayanan
2021-04-20 17:36 ` Dave Hansen
2021-04-20 19:20 ` Kuppuswamy, Sathyanarayanan
2021-04-20 19:59 ` Dave Hansen
2021-04-20 23:12 ` Kuppuswamy, Sathyanarayanan
2021-04-20 23:42 ` Dave Hansen
2021-04-23 1:09 ` Kuppuswamy, Sathyanarayanan
2021-04-23 1:21 ` Dave Hansen
2021-04-23 1:35 ` Andi Kleen
2021-04-23 15:15 ` Sean Christopherson
2021-04-23 15:28 ` Dan Williams
2021-04-23 15:38 ` Andi Kleen
2021-04-23 15:50 ` Sean Christopherson
2021-04-23 15:47 ` Andi Kleen
2021-04-23 18:18 ` Kuppuswamy, Sathyanarayanan
2021-04-20 23:53 ` Dan Williams
2021-04-20 23:59 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 10/26] x86/io: Allow to override inX() and outX() implementation Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 11/26] x86/tdx: Handle port I/O Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 12/26] x86/tdx: Handle in-kernel MMIO Kuppuswamy Sathyanarayanan
2021-04-01 19:56 ` Dave Hansen
2021-04-01 22:26 ` Sean Christopherson
2021-04-01 22:53 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 13/26] x86/tdx: Handle MWAIT, MONITOR and WBINVD Kuppuswamy Sathyanarayanan
2021-02-05 23:43 ` Andy Lutomirski
2021-02-05 23:54 ` Kuppuswamy, Sathyanarayanan
2021-02-06 1:05 ` Andy Lutomirski
2021-03-27 0:18 ` [PATCH v1 1/1] " Kuppuswamy Sathyanarayanan
2021-03-27 2:40 ` Andy Lutomirski
2021-03-27 3:40 ` Kuppuswamy, Sathyanarayanan
2021-03-27 16:03 ` Andy Lutomirski
2021-03-27 22:54 ` [PATCH v2 " Kuppuswamy Sathyanarayanan
2021-03-29 17:14 ` Dave Hansen
2021-03-29 21:55 ` Kuppuswamy, Sathyanarayanan
2021-03-29 22:02 ` Dave Hansen
2021-03-29 22:09 ` Kuppuswamy, Sathyanarayanan
2021-03-29 22:12 ` Dave Hansen
2021-03-29 22:42 ` Kuppuswamy, Sathyanarayanan
2021-03-29 23:16 ` [PATCH v3 " Kuppuswamy Sathyanarayanan
2021-03-29 23:23 ` Andy Lutomirski
2021-03-29 23:37 ` Kuppuswamy, Sathyanarayanan
2021-03-29 23:42 ` Sean Christopherson
2021-03-29 23:58 ` Andy Lutomirski
2021-03-30 2:04 ` Andi Kleen
2021-03-30 2:58 ` Andy Lutomirski
2021-03-30 15:14 ` Sean Christopherson
2021-03-30 16:37 ` Andy Lutomirski
2021-03-30 16:57 ` Sean Christopherson
2021-04-07 15:24 ` Andi Kleen
2021-03-31 21:09 ` [PATCH v4 " Kuppuswamy Sathyanarayanan
2021-03-31 21:49 ` Dave Hansen
2021-03-31 22:29 ` Kuppuswamy, Sathyanarayanan
2021-03-31 21:53 ` Sean Christopherson
2021-03-31 22:00 ` Dave Hansen
2021-03-31 22:06 ` Sean Christopherson
2021-03-31 22:11 ` Dave Hansen
2021-03-31 22:28 ` Kuppuswamy, Sathyanarayanan
2021-03-31 22:32 ` Sean Christopherson
2021-03-31 22:34 ` Dave Hansen
2021-04-01 3:28 ` Andi Kleen
2021-04-01 3:46 ` Dave Hansen
2021-04-01 4:24 ` Andi Kleen
2021-04-01 4:51 ` [PATCH v5 " Kuppuswamy Sathyanarayanan
2021-03-29 23:39 ` [PATCH v3 " Sean Christopherson
2021-03-29 23:38 ` Dave Hansen
2021-03-30 4:56 ` [PATCH v1 " Xiaoyao Li
2021-03-30 15:00 ` Andi Kleen
2021-03-30 15:10 ` Dave Hansen
2021-03-30 17:02 ` Kuppuswamy, Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 14/26] ACPI: tables: Add multiprocessor wake-up support Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 15/26] x86/boot: Add a trampoline for APs booting in 64-bit mode Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 16/26] x86/boot: Avoid #VE during compressed boot for TDX platforms Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 17/26] x86/boot: Avoid unnecessary #VE during boot process Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 18/26] x86/topology: Disable CPU hotplug support for TDX platforms Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 19/26] x86/tdx: Forcefully disable legacy PIC for TDX guests Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 20/26] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 21/26] x86/mm: Move force_dma_unencrypted() to common code Kuppuswamy Sathyanarayanan
2021-04-01 20:06 ` Dave Hansen
2021-04-06 15:37 ` Kirill A. Shutemov
2021-04-06 16:11 ` Dave Hansen
2021-04-06 16:37 ` Kirill A. Shutemov
2021-02-05 23:38 ` [RFC v1 22/26] x86/tdx: Exclude Shared bit from __PHYSICAL_MASK Kuppuswamy Sathyanarayanan
2021-04-01 20:13 ` Dave Hansen
2021-04-06 15:54 ` Kirill A. Shutemov
2021-04-06 16:12 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 23/26] x86/tdx: Make pages shared in ioremap() Kuppuswamy Sathyanarayanan
2021-04-01 20:26 ` Dave Hansen
2021-04-06 16:00 ` Kirill A. Shutemov
2021-04-06 16:14 ` Dave Hansen
2021-02-05 23:38 ` [RFC v1 24/26] x86/tdx: Add helper to do MapGPA TDVMALL Kuppuswamy Sathyanarayanan
2021-02-05 23:38 ` [RFC v1 25/26] x86/tdx: Make DMA pages shared Kuppuswamy Sathyanarayanan
2021-04-01 21:01 ` Dave Hansen
2021-04-06 16:31 ` Kirill A. Shutemov [this message]
2021-04-06 16:38 ` Dave Hansen
2021-04-06 17:16 ` Sean Christopherson
2021-02-05 23:38 ` [RFC v1 26/26] x86/kvm: Use bounce buffers for TD guest Kuppuswamy Sathyanarayanan
2021-04-01 21:17 ` Dave Hansen
2021-02-06 3:04 ` Test Email sathyanarayanan.kuppuswamy
2021-02-06 6:24 ` [RFC v1 00/26] Add TDX Guest Support sathyanarayanan.kuppuswamy
2021-03-31 21:38 ` Kuppuswamy, Sathyanarayanan
2021-04-02 0:02 ` Dave Hansen
2021-04-02 2:48 ` Andi Kleen
2021-04-02 15:27 ` Dave Hansen
2021-04-02 21:32 ` Andi Kleen
2021-04-03 16:26 ` Dave Hansen
2021-04-03 17:28 ` Andi Kleen
2021-04-04 15:02 ` Dave Hansen
2021-04-12 17:24 ` Dan Williams
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