| Message ID | 20160822223749.29880.10183.stgit@tlendack-t1.amdoffice.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Aug 22, 2016 at 05:37:49PM -0500, Tom Lendacky wrote: > This patch adds support to be change the memory encryption attribute for > one or more memory pages. > > Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/include/asm/cacheflush.h | 3 + > arch/x86/include/asm/mem_encrypt.h | 13 ++++++ > arch/x86/mm/mem_encrypt.c | 43 +++++++++++++++++++++ > arch/x86/mm/pageattr.c | 75 ++++++++++++++++++++++++++++++++++++ > 4 files changed, 134 insertions(+) ... > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c > index 72c292d..0ba9382 100644 > --- a/arch/x86/mm/pageattr.c > +++ b/arch/x86/mm/pageattr.c > @@ -1728,6 +1728,81 @@ int set_memory_4k(unsigned long addr, int numpages) > __pgprot(0), 1, 0, NULL); > } > > +static int __set_memory_enc_dec(struct cpa_data *cpa) > +{ > + unsigned long addr; > + int numpages; > + int ret; > + > + if (*cpa->vaddr & ~PAGE_MASK) { > + *cpa->vaddr &= PAGE_MASK; > + > + /* People should not be passing in unaligned addresses */ > + WARN_ON_ONCE(1); Let's make this more user-friendly: if (WARN_ONCE(*cpa->vaddr & ~PAGE_MASK, "Misaligned address: 0x%lx\n", *cpa->vaddr)) *cpa->vaddr &= PAGE_MASK; > + } > + > + addr = *cpa->vaddr; > + numpages = cpa->numpages; > + > + /* Must avoid aliasing mappings in the highmem code */ > + kmap_flush_unused(); > + vm_unmap_aliases(); > + > + ret = __change_page_attr_set_clr(cpa, 1); > + > + /* Check whether we really changed something */ > + if (!(cpa->flags & CPA_FLUSHTLB)) > + goto out; > + > + /* > + * On success we use CLFLUSH, when the CPU supports it to > + * avoid the WBINVD. > + */ > + if (!ret && static_cpu_has(X86_FEATURE_CLFLUSH)) > + cpa_flush_range(addr, numpages, 1); > + else > + cpa_flush_all(1); So if we fail (ret != 0) we do WBINVD unconditionally even if we don't have to? Don't you want this instead: ret = __change_page_attr_set_clr(cpa, 1); if (ret) goto out; /* Check whether we really changed something */ if (!(cpa->flags & CPA_FLUSHTLB)) goto out; /* * On success we use CLFLUSH, when the CPU supports it to * avoid the WBINVD. */ if (static_cpu_has(X86_FEATURE_CLFLUSH)) cpa_flush_range(addr, numpages, 1); else cpa_flush_all(1); out: return ret; } ?
On 09/09/2016 12:23 PM, Borislav Petkov wrote: > On Mon, Aug 22, 2016 at 05:37:49PM -0500, Tom Lendacky wrote: >> This patch adds support to be change the memory encryption attribute for >> one or more memory pages. >> >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> >> --- >> arch/x86/include/asm/cacheflush.h | 3 + >> arch/x86/include/asm/mem_encrypt.h | 13 ++++++ >> arch/x86/mm/mem_encrypt.c | 43 +++++++++++++++++++++ >> arch/x86/mm/pageattr.c | 75 ++++++++++++++++++++++++++++++++++++ >> 4 files changed, 134 insertions(+) > > ... > >> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c >> index 72c292d..0ba9382 100644 >> --- a/arch/x86/mm/pageattr.c >> +++ b/arch/x86/mm/pageattr.c >> @@ -1728,6 +1728,81 @@ int set_memory_4k(unsigned long addr, int numpages) >> __pgprot(0), 1, 0, NULL); >> } >> >> +static int __set_memory_enc_dec(struct cpa_data *cpa) >> +{ >> + unsigned long addr; >> + int numpages; >> + int ret; >> + >> + if (*cpa->vaddr & ~PAGE_MASK) { >> + *cpa->vaddr &= PAGE_MASK; >> + >> + /* People should not be passing in unaligned addresses */ >> + WARN_ON_ONCE(1); > > Let's make this more user-friendly: > > if (WARN_ONCE(*cpa->vaddr & ~PAGE_MASK, "Misaligned address: 0x%lx\n", *cpa->vaddr)) > *cpa->vaddr &= PAGE_MASK; Will do. > >> + } >> + >> + addr = *cpa->vaddr; >> + numpages = cpa->numpages; >> + >> + /* Must avoid aliasing mappings in the highmem code */ >> + kmap_flush_unused(); >> + vm_unmap_aliases(); >> + >> + ret = __change_page_attr_set_clr(cpa, 1); >> + >> + /* Check whether we really changed something */ >> + if (!(cpa->flags & CPA_FLUSHTLB)) >> + goto out; >> + >> + /* >> + * On success we use CLFLUSH, when the CPU supports it to >> + * avoid the WBINVD. >> + */ >> + if (!ret && static_cpu_has(X86_FEATURE_CLFLUSH)) >> + cpa_flush_range(addr, numpages, 1); >> + else >> + cpa_flush_all(1); > > So if we fail (ret != 0) we do WBINVD unconditionally even if we don't > have to? Looking at __change_page_attr_set_clr() isn't it possible for some of the pages to be changed before an error is encountered since it is looping? If so, we may still need to flush. The CPA_FLUSHTLB flag should take care of a failing case where no attributes have actually been changed. Thanks, Tom > > Don't you want this instead: > > ret = __change_page_attr_set_clr(cpa, 1); > if (ret) > goto out; > > /* Check whether we really changed something */ > if (!(cpa->flags & CPA_FLUSHTLB)) > goto out; > > /* > * On success we use CLFLUSH, when the CPU supports it to > * avoid the WBINVD. > */ > if (static_cpu_has(X86_FEATURE_CLFLUSH)) > cpa_flush_range(addr, numpages, 1); > else > cpa_flush_all(1); > > out: > return ret; > } > > ? > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Sep 12, 2016 at 10:41:29AM -0500, Tom Lendacky wrote: > Looking at __change_page_attr_set_clr() isn't it possible for some of > the pages to be changed before an error is encountered since it is > looping? If so, we may still need to flush. The CPA_FLUSHTLB flag > should take care of a failing case where no attributes have actually > been changed. Ah, yes, ok, then yours is correct.
diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h index 61518cf..bfb08e5 100644 --- a/arch/x86/include/asm/cacheflush.h +++ b/arch/x86/include/asm/cacheflush.h @@ -13,6 +13,7 @@ * Executability : eXeutable, NoteXecutable * Read/Write : ReadOnly, ReadWrite * Presence : NotPresent + * Encryption : ENCrypted, DECrypted * * Within a category, the attributes are mutually exclusive. * @@ -48,6 +49,8 @@ int set_memory_ro(unsigned long addr, int numpages); int set_memory_rw(unsigned long addr, int numpages); int set_memory_np(unsigned long addr, int numpages); int set_memory_4k(unsigned long addr, int numpages); +int set_memory_enc(unsigned long addr, int numpages); +int set_memory_dec(unsigned long addr, int numpages); int set_memory_array_uc(unsigned long *addr, int addrinarray); int set_memory_array_wc(unsigned long *addr, int addrinarray); diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index 2785493..5616ed1 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -23,6 +23,9 @@ extern unsigned long sme_me_mask; u8 sme_get_me_loss(void); +int sme_set_mem_enc(void *vaddr, unsigned long size); +int sme_set_mem_dec(void *vaddr, unsigned long size); + void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size); void __init sme_early_mem_dec(resource_size_t paddr, @@ -44,6 +47,16 @@ static inline u8 sme_get_me_loss(void) return 0; } +static inline int sme_set_mem_enc(void *vaddr, unsigned long size) +{ + return 0; +} + +static inline int sme_set_mem_dec(void *vaddr, unsigned long size) +{ + return 0; +} + static inline void __init sme_early_mem_enc(resource_size_t paddr, unsigned long size) { diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index f35a646..b0f39c5 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -14,12 +14,55 @@ #include <linux/mm.h> #include <asm/mem_encrypt.h> +#include <asm/cacheflush.h> #include <asm/tlbflush.h> #include <asm/fixmap.h> /* Buffer used for early in-place encryption by BSP, no locking needed */ static char me_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE); +int sme_set_mem_enc(void *vaddr, unsigned long size) +{ + unsigned long addr, numpages; + + if (!sme_me_mask) + return 0; + + addr = (unsigned long)vaddr & PAGE_MASK; + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT; + + /* + * The set_memory_xxx functions take an integer for numpages, make + * sure it doesn't exceed that. + */ + if (numpages > INT_MAX) + return -EINVAL; + + return set_memory_enc(addr, numpages); +} +EXPORT_SYMBOL_GPL(sme_set_mem_enc); + +int sme_set_mem_dec(void *vaddr, unsigned long size) +{ + unsigned long addr, numpages; + + if (!sme_me_mask) + return 0; + + addr = (unsigned long)vaddr & PAGE_MASK; + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT; + + /* + * The set_memory_xxx functions take an integer for numpages, make + * sure it doesn't exceed that. + */ + if (numpages > INT_MAX) + return -EINVAL; + + return set_memory_dec(addr, numpages); +} +EXPORT_SYMBOL_GPL(sme_set_mem_dec); + /* * This routine does not change the underlying encryption setting of the * page(s) that map this memory. It assumes that eventually the memory is diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 72c292d..0ba9382 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1728,6 +1728,81 @@ int set_memory_4k(unsigned long addr, int numpages) __pgprot(0), 1, 0, NULL); } +static int __set_memory_enc_dec(struct cpa_data *cpa) +{ + unsigned long addr; + int numpages; + int ret; + + if (*cpa->vaddr & ~PAGE_MASK) { + *cpa->vaddr &= PAGE_MASK; + + /* People should not be passing in unaligned addresses */ + WARN_ON_ONCE(1); + } + + addr = *cpa->vaddr; + numpages = cpa->numpages; + + /* Must avoid aliasing mappings in the highmem code */ + kmap_flush_unused(); + vm_unmap_aliases(); + + ret = __change_page_attr_set_clr(cpa, 1); + + /* Check whether we really changed something */ + if (!(cpa->flags & CPA_FLUSHTLB)) + goto out; + + /* + * On success we use CLFLUSH, when the CPU supports it to + * avoid the WBINVD. + */ + if (!ret && static_cpu_has(X86_FEATURE_CLFLUSH)) + cpa_flush_range(addr, numpages, 1); + else + cpa_flush_all(1); + +out: + return ret; +} + +int set_memory_enc(unsigned long addr, int numpages) +{ + struct cpa_data cpa; + + if (!sme_me_mask) + return 0; + + memset(&cpa, 0, sizeof(cpa)); + cpa.vaddr = &addr; + cpa.numpages = numpages; + cpa.mask_set = __pgprot(_PAGE_ENC); + cpa.mask_clr = __pgprot(0); + cpa.pgd = init_mm.pgd; + + return __set_memory_enc_dec(&cpa); +} +EXPORT_SYMBOL(set_memory_enc); + +int set_memory_dec(unsigned long addr, int numpages) +{ + struct cpa_data cpa; + + if (!sme_me_mask) + return 0; + + memset(&cpa, 0, sizeof(cpa)); + cpa.vaddr = &addr; + cpa.numpages = numpages; + cpa.mask_set = __pgprot(0); + cpa.mask_clr = __pgprot(_PAGE_ENC); + cpa.pgd = init_mm.pgd; + + return __set_memory_enc_dec(&cpa); +} +EXPORT_SYMBOL(set_memory_dec); + int set_pages_uc(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page);
This patch adds support to be change the memory encryption attribute for one or more memory pages. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> --- arch/x86/include/asm/cacheflush.h | 3 + arch/x86/include/asm/mem_encrypt.h | 13 ++++++ arch/x86/mm/mem_encrypt.c | 43 +++++++++++++++++++++ arch/x86/mm/pageattr.c | 75 ++++++++++++++++++++++++++++++++++++ 4 files changed, 134 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html