From: Borislav Petkov <bp@alien8.de>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
iommu@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-graphics-maintainer@vmware.com,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
Brijesh Singh <brijesh.singh@amd.com>,
Joerg Roedel <joro@8bytes.org>, Andi Kleen <ak@linux.intel.com>,
Sathyanarayanan Kuppuswamy
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Tianyu Lan <Tianyu.Lan@microsoft.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>, Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH v2 05/12] x86/sme: Replace occurrences of sme_active() with prot_guest_has()
Date: Tue, 17 Aug 2021 11:00:56 +0200 [thread overview]
Message-ID: <YRt6yCNCBLwyyx5X@zn.tnic> (raw)
In-Reply-To: <c6c38d6253dc78381f9ff0f1823b6ee5ddeefacc.1628873970.git.thomas.lendacky@amd.com>
On Fri, Aug 13, 2021 at 11:59:24AM -0500, Tom Lendacky wrote:
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index edc67ddf065d..5635ca9a1fbe 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -144,7 +144,7 @@ void __init sme_unmap_bootdata(char *real_mode_data)
> struct boot_params *boot_data;
> unsigned long cmdline_paddr;
>
> - if (!sme_active())
> + if (!amd_prot_guest_has(PATTR_SME))
> return;
>
> /* Get the command line address before unmapping the real_mode_data */
> @@ -164,7 +164,7 @@ void __init sme_map_bootdata(char *real_mode_data)
> struct boot_params *boot_data;
> unsigned long cmdline_paddr;
>
> - if (!sme_active())
> + if (!amd_prot_guest_has(PATTR_SME))
> return;
>
> __sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
> @@ -378,7 +378,7 @@ bool sev_active(void)
> return sev_status & MSR_AMD64_SEV_ENABLED;
> }
>
> -bool sme_active(void)
> +static bool sme_active(void)
Just get rid of it altogether. Also, there's an
EXPORT_SYMBOL_GPL(sev_active);
which needs to go under the actual function. Here's a diff ontop:
---
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 5635ca9a1fbe..a3a2396362a5 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -364,8 +364,9 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
/*
* SME and SEV are very similar but they are not the same, so there are
* times that the kernel will need to distinguish between SME and SEV. The
- * sme_active() and sev_active() functions are used for this. When a
- * distinction isn't needed, the mem_encrypt_active() function can be used.
+ * PATTR_HOST_MEM_ENCRYPT and PATTR_GUEST_MEM_ENCRYPT flags to
+ * amd_prot_guest_has() are used for this. When a distinction isn't needed,
+ * the mem_encrypt_active() function can be used.
*
* The trampoline code is a good example for this requirement. Before
* paging is activated, SME will access all memory as decrypted, but SEV
@@ -377,11 +378,6 @@ bool sev_active(void)
{
return sev_status & MSR_AMD64_SEV_ENABLED;
}
-
-static bool sme_active(void)
-{
- return sme_me_mask && !sev_active();
-}
EXPORT_SYMBOL_GPL(sev_active);
/* Needs to be called from non-instrumentable code */
@@ -398,7 +394,7 @@ bool amd_prot_guest_has(unsigned int attr)
case PATTR_SME:
case PATTR_HOST_MEM_ENCRYPT:
- return sme_active();
+ return sme_me_mask && !sev_active();
case PATTR_SEV:
case PATTR_GUEST_MEM_ENCRYPT:
> {
> return sme_me_mask && !sev_active();
> }
> @@ -428,7 +428,7 @@ bool force_dma_unencrypted(struct device *dev)
> * device does not support DMA to addresses that include the
> * encryption mask.
> */
> - if (sme_active()) {
> + if (amd_prot_guest_has(PATTR_SME)) {
So I'm not sure: you add PATTR_SME which you call with
amd_prot_guest_has() and PATTR_HOST_MEM_ENCRYPT which you call with
prot_guest_has() and they both end up being the same thing on AMD.
So why even bother with PATTR_SME?
This is only going to cause confusion later and I'd say let's simply use
prot_guest_has(PATTR_HOST_MEM_ENCRYPT) everywhere...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-08-17 9:00 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 16:59 [PATCH v2 00/12] Implement generic prot_guest_has() helper function Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 01/12] x86/ioremap: Selectively build arch override encryption functions Tom Lendacky
2021-08-14 15:25 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 02/12] mm: Introduce a function to check for virtualization protection features Tom Lendacky
2021-08-13 17:19 ` Kuppuswamy, Sathyanarayanan
2021-08-14 18:32 ` Borislav Petkov
2021-08-14 18:49 ` Tom Lendacky
2021-08-19 9:46 ` Christoph Hellwig
2021-08-19 16:39 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has() Tom Lendacky
2021-08-14 19:08 ` Borislav Petkov
2021-08-15 13:53 ` Tom Lendacky
2021-08-15 14:39 ` Borislav Petkov
2021-08-17 15:22 ` Tom Lendacky
2021-08-17 18:39 ` Borislav Petkov
2021-08-19 9:52 ` Christoph Hellwig
2021-08-19 17:26 ` Borislav Petkov
2021-08-19 18:33 ` Tom Lendacky
2021-08-19 19:57 ` Kuppuswamy, Sathyanarayanan
2021-08-24 7:14 ` Christoph Hellwig
2021-08-13 16:59 ` [PATCH v2 04/12] powerpc/pseries/svm: Add a powerpc " Tom Lendacky
2021-08-17 8:35 ` Borislav Petkov
2021-08-17 14:11 ` Tom Lendacky
2021-08-17 12:38 ` Michael Ellerman
2021-08-19 9:55 ` Christoph Hellwig
2021-08-19 18:34 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 05/12] x86/sme: Replace occurrences of sme_active() with prot_guest_has() Tom Lendacky
2021-08-17 9:00 ` Borislav Petkov [this message]
2021-08-17 14:46 ` Tom Lendacky
2021-08-17 18:41 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 06/12] x86/sev: Replace occurrences of sev_active() " Tom Lendacky
2021-08-17 10:02 ` Borislav Petkov
2021-08-17 15:26 ` Tom Lendacky
2021-08-17 18:43 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 07/12] x86/sev: Replace occurrences of sev_es_active() " Tom Lendacky
2021-08-17 10:06 ` Borislav Petkov
2021-08-13 16:59 ` [PATCH v2 08/12] treewide: Replace the use of mem_encrypt_active() " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 09/12] mm: Remove the now unused mem_encrypt_active() function Tom Lendacky
2021-08-17 10:22 ` Borislav Petkov
2021-08-17 10:24 ` Borislav Petkov
2021-08-17 15:30 ` Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 10/12] x86/sev: " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 11/12] powerpc/pseries/svm: " Tom Lendacky
2021-08-13 16:59 ` [PATCH v2 12/12] s390/mm: " Tom Lendacky
2021-08-13 17:22 ` [PATCH v2 00/12] Implement generic prot_guest_has() helper function Tom Lendacky
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