Re: [PATCH v2 05/12] x86/sme: Replace occurrences of sme_active() with prot_guest_has()
From: Borislav Petkov <bp@alien8.de>
Date: 2021-08-17 09:00:37
Also in:
amd-gfx, dri-devel, kexec, kvm, linux-efi, linux-fsdevel, linux-iommu, linux-s390, lkml, platform-driver-x86
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
On Fri, Aug 13, 2021 at 11:59:24AM -0500, Tom Lendacky wrote:
quoted hunk ↗ jump to hunk
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:
quoted hunk ↗ jump to hunk
{ 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