| Message ID | 20220614120231.48165-15-kirill.shutemov@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | mm, x86/cc: Implement support for unaccepted memory | expand |
On 6/14/22 05:02, Kirill A. Shutemov wrote: > static inline void __accept_memory(phys_addr_t start, phys_addr_t end) > { > /* Platform-specific memory-acceptance call goes here */ > - error("Cannot accept memory"); > + if (is_tdx_guest()) > + tdx_accept_memory(start, end); > + else > + error("Cannot accept memory: unknown platform\n"); > } There are quite a few of these if (tdx()) ... conditions in common code here. Shouldn't this be something like a CC_ATTR_MEM_ACCEPT? if (cc_platform_has(CC_ATTR_MEM_ACCEPT)) cc_accept_memory(...); else error("Cannot accept memory: unknown platform\n"); I understand that TDX is the first one to the party. Is this the time to add the cc_ infrastructure?
On Fri, Jun 24, 2022 at 09:22:03AM -0700, Dave Hansen wrote: > On 6/14/22 05:02, Kirill A. Shutemov wrote: > > static inline void __accept_memory(phys_addr_t start, phys_addr_t end) > > { > > /* Platform-specific memory-acceptance call goes here */ > > - error("Cannot accept memory"); > > + if (is_tdx_guest()) > > + tdx_accept_memory(start, end); > > + else > > + error("Cannot accept memory: unknown platform\n"); > > } > > There are quite a few of these > > if (tdx()) > ... > > conditions in common code here. Shouldn't this be something like a > CC_ATTR_MEM_ACCEPT? > > if (cc_platform_has(CC_ATTR_MEM_ACCEPT)) > cc_accept_memory(...); > else > error("Cannot accept memory: unknown platform\n"); > > I understand that TDX is the first one to the party. Is this the time > to add the cc_ infrastructure? We need if tdx() check *somewhere* as how exactly memory gets accepted is specific to a particular platform. There are two callsites where memory acceptance happens. One of them is in boot stub where we don't have cc_ infrastructure. So it will boil down to a single cc_accept_memory() that will have 'if tdx()' inside. I don't see much sense in the exercise. We can as well keep the 'if' in accept_memory().
On Tue, Jun 14, 2022 at 03:02:31PM +0300, Kirill A. Shutemov wrote: > +static bool is_tdx_guest(void) > +{ > + static bool once; > + static bool is_tdx; > + > + if (!IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) > + return false; > + > + if (!once) { > + u32 eax, sig[3]; > + > + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, > + &sig[0], &sig[2], &sig[1]); > + is_tdx = !memcmp(TDX_IDENT, sig, sizeof(sig)); > + once = true; > + } > + > + return is_tdx; > +} early_tdx_detect() already calls this CPUID function. It assigns function pointers too. So why can't you assign an accept_memory() function pointer there and get rid of this sprinkled if (tdx) everywhere? > diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c > index 918a7606f53c..8518a75e5dd5 100644 > --- a/arch/x86/boot/compressed/tdx.c > +++ b/arch/x86/boot/compressed/tdx.c > @@ -3,12 +3,15 @@ > #include "../cpuflags.h" > #include "../string.h" > #include "../io.h" > +#include "align.h" > #include "error.h" > +#include "pgtable_types.h" > > #include <vdso/limits.h> > #include <uapi/asm/vmx.h> > > #include <asm/shared/tdx.h> > +#include <asm/page_types.h> > > /* Called from __tdx_hypercall() for unrecoverable failure */ > void __tdx_hypercall_failed(void) > @@ -75,3 +78,78 @@ void early_tdx_detect(void) > pio_ops.f_outb = tdx_outb; > pio_ops.f_outw = tdx_outw; > } > + > +static unsigned long try_accept_one(phys_addr_t start, unsigned long len, > + enum pg_level level) That's pretty much a copy of the same function in arch/x86/coco/tdx/tdx.c. Yeah, you need a tdx-shared.c which you include in both places just like it is done with sev-shared.c ... > +void tdx_accept_memory(phys_addr_t start, phys_addr_t end) That one too. > +{ > + /* > + * Notify the VMM about page mapping conversion. More info about ABI > + * can be found in TDX Guest-Host-Communication Interface (GHCI), > + * section "TDG.VP.VMCALL<MapGPA>" > + */ > + if (_tdx_hypercall(TDVMCALL_MAP_GPA, start, end - start, 0, 0)) > + error("Accepting memory failed\n"); > + > + /* > + * For shared->private conversion, accept the page using > + * TDX_ACCEPT_PAGE TDX module call. > + */ > + while (start < end) { > + unsigned long len = end - start; > + unsigned long accept_size; > + > + /* > + * Try larger accepts first. It gives chance to VMM to keep > + * 1G/2M Secure EPT entries where possible and speeds up > + * process by cutting number of hypercalls (if successful). > + */ > + > + accept_size = try_accept_one(start, len, PG_LEVEL_1G); > + if (!accept_size) > + accept_size = try_accept_one(start, len, PG_LEVEL_2M); > + if (!accept_size) > + accept_size = try_accept_one(start, len, PG_LEVEL_4K); > + if (!accept_size) > + error("Accepting memory failed\n"); > + start += accept_size; This series of calls to try_accept_one() appear in at least three places. Please carve them out into a separate function can put it in tdx-shared.c.
On Tue, Jul 26, 2022 at 04:51:16PM +0200, Borislav Petkov wrote: > On Tue, Jun 14, 2022 at 03:02:31PM +0300, Kirill A. Shutemov wrote: > > +static bool is_tdx_guest(void) > > +{ > > + static bool once; > > + static bool is_tdx; > > + > > + if (!IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) > > + return false; > > + > > + if (!once) { > > + u32 eax, sig[3]; > > + > > + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, > > + &sig[0], &sig[2], &sig[1]); > > + is_tdx = !memcmp(TDX_IDENT, sig, sizeof(sig)); > > + once = true; > > + } > > + > > + return is_tdx; > > +} > > early_tdx_detect() already calls this CPUID function. It assigns > function pointers too. > > So why can't you assign an accept_memory() function pointer there and > get rid of this sprinkled if (tdx) everywhere? This code called from EFI stub which runs before decompressor code and therefore before early_tdx_detect(). > > diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c > > index 918a7606f53c..8518a75e5dd5 100644 > > --- a/arch/x86/boot/compressed/tdx.c > > +++ b/arch/x86/boot/compressed/tdx.c > > @@ -3,12 +3,15 @@ > > #include "../cpuflags.h" > > #include "../string.h" > > #include "../io.h" > > +#include "align.h" > > #include "error.h" > > +#include "pgtable_types.h" > > > > #include <vdso/limits.h> > > #include <uapi/asm/vmx.h> > > > > #include <asm/shared/tdx.h> > > +#include <asm/page_types.h> > > > > /* Called from __tdx_hypercall() for unrecoverable failure */ > > void __tdx_hypercall_failed(void) > > @@ -75,3 +78,78 @@ void early_tdx_detect(void) > > pio_ops.f_outb = tdx_outb; > > pio_ops.f_outw = tdx_outw; > > } > > + > > +static unsigned long try_accept_one(phys_addr_t start, unsigned long len, > > + enum pg_level level) > > That's pretty much a copy of the same function in arch/x86/coco/tdx/tdx.c. > > Yeah, you need a tdx-shared.c which you include in both places just like > it is done with sev-shared.c Okay, will look into this. > > + accept_size = try_accept_one(start, len, PG_LEVEL_1G); > > + if (!accept_size) > > + accept_size = try_accept_one(start, len, PG_LEVEL_2M); > > + if (!accept_size) > > + accept_size = try_accept_one(start, len, PG_LEVEL_4K); > > + if (!accept_size) > > + error("Accepting memory failed\n"); > > + start += accept_size; > > This series of calls to try_accept_one() appear in at least three > places. Please carve them out into a separate function can put it in > tdx-shared.c. Okay.
On Tue, Aug 09, 2022 at 02:45:44PM +0300, Kirill A. Shutemov wrote: > This code called from EFI stub which runs before decompressor code and > therefore before early_tdx_detect(). Then pls call that function early_is_tdx_guest() and slap a comment above it explaining why it needs to be a separate thing. Thx.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9783ebc4e021..80683afa5749 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -892,6 +892,7 @@ config INTEL_TDX_GUEST select ARCH_HAS_CC_PLATFORM select X86_MEM_ENCRYPT select X86_MCE + select UNACCEPTED_MEMORY help Support running as a guest under Intel TDX. Without this support, the guest kernel can not boot or run under TDX. diff --git a/arch/x86/boot/compressed/mem.c b/arch/x86/boot/compressed/mem.c index b45458af00ca..48e36e640da1 100644 --- a/arch/x86/boot/compressed/mem.c +++ b/arch/x86/boot/compressed/mem.c @@ -5,6 +5,8 @@ #include "error.h" #include "find.h" #include "math.h" +#include "tdx.h" +#include <asm/shared/tdx.h> #define PMD_SHIFT 21 #define PMD_SIZE (_AC(1, UL) << PMD_SHIFT) @@ -12,10 +14,33 @@ extern struct boot_params *boot_params; +static bool is_tdx_guest(void) +{ + static bool once; + static bool is_tdx; + + if (!IS_ENABLED(CONFIG_INTEL_TDX_GUEST)) + return false; + + if (!once) { + u32 eax, sig[3]; + + cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, + &sig[0], &sig[2], &sig[1]); + is_tdx = !memcmp(TDX_IDENT, sig, sizeof(sig)); + once = true; + } + + return is_tdx; +} + static inline void __accept_memory(phys_addr_t start, phys_addr_t end) { /* Platform-specific memory-acceptance call goes here */ - error("Cannot accept memory"); + if (is_tdx_guest()) + tdx_accept_memory(start, end); + else + error("Cannot accept memory: unknown platform\n"); } /* diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index 918a7606f53c..8518a75e5dd5 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -3,12 +3,15 @@ #include "../cpuflags.h" #include "../string.h" #include "../io.h" +#include "align.h" #include "error.h" +#include "pgtable_types.h" #include <vdso/limits.h> #include <uapi/asm/vmx.h> #include <asm/shared/tdx.h> +#include <asm/page_types.h> /* Called from __tdx_hypercall() for unrecoverable failure */ void __tdx_hypercall_failed(void) @@ -75,3 +78,78 @@ void early_tdx_detect(void) pio_ops.f_outb = tdx_outb; pio_ops.f_outw = tdx_outw; } + +static unsigned long try_accept_one(phys_addr_t start, unsigned long len, + enum pg_level level) +{ + unsigned long accept_size = PAGE_SIZE << ((level - 1) * PTE_SHIFT); + u64 tdcall_rcx; + u8 page_size; + + if (!IS_ALIGNED(start, accept_size)) + return 0; + + if (len < accept_size) + return 0; + + /* + * Pass the page physical address to the TDX module to accept the + * pending, private page. + * + * Bits 2:0 of RCX encode page size: 0 - 4K, 1 - 2M, 2 - 1G. + */ + switch (level) { + case PG_LEVEL_4K: + page_size = 0; + break; + case PG_LEVEL_2M: + page_size = 1; + break; + case PG_LEVEL_1G: + page_size = 2; + break; + default: + return 0; + } + + tdcall_rcx = start | page_size; + if (__tdx_module_call(TDX_ACCEPT_PAGE, tdcall_rcx, 0, 0, 0, NULL)) + return 0; + + return accept_size; +} + +void tdx_accept_memory(phys_addr_t start, phys_addr_t end) +{ + /* + * Notify the VMM about page mapping conversion. More info about ABI + * can be found in TDX Guest-Host-Communication Interface (GHCI), + * section "TDG.VP.VMCALL<MapGPA>" + */ + if (_tdx_hypercall(TDVMCALL_MAP_GPA, start, end - start, 0, 0)) + error("Accepting memory failed\n"); + + /* + * For shared->private conversion, accept the page using + * TDX_ACCEPT_PAGE TDX module call. + */ + while (start < end) { + unsigned long len = end - start; + unsigned long accept_size; + + /* + * Try larger accepts first. It gives chance to VMM to keep + * 1G/2M Secure EPT entries where possible and speeds up + * process by cutting number of hypercalls (if successful). + */ + + accept_size = try_accept_one(start, len, PG_LEVEL_1G); + if (!accept_size) + accept_size = try_accept_one(start, len, PG_LEVEL_2M); + if (!accept_size) + accept_size = try_accept_one(start, len, PG_LEVEL_4K); + if (!accept_size) + error("Accepting memory failed\n"); + start += accept_size; + } +} diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index b10c95307f6e..8240f04d3646 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -664,16 +664,9 @@ static unsigned long try_accept_one(phys_addr_t start, unsigned long len, return accept_size; } -/* - * Inform the VMM of the guest's intent for this physical page: shared with - * the VMM or private to the guest. The VMM is expected to change its mapping - * of the page in response. - */ -static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) +static bool tdx_enc_status_changed_phys(phys_addr_t start, phys_addr_t end, + bool enc) { - phys_addr_t start = __pa(vaddr); - phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE); - if (!enc) { /* Set the shared (decrypted) bits: */ start |= cc_mkdec(0); @@ -719,6 +712,25 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) return true; } +void tdx_accept_memory(phys_addr_t start, phys_addr_t end) +{ + if (!tdx_enc_status_changed_phys(start, end, true)) + panic("Accepting memory failed: %#llx-%#llx\n", start, end); +} + +/* + * Inform the VMM of the guest's intent for this physical page: shared with + * the VMM or private to the guest. The VMM is expected to change its mapping + * of the page in response. + */ +static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc) +{ + phys_addr_t start = __pa(vaddr); + phys_addr_t end = __pa(vaddr + numpages * PAGE_SIZE); + + return tdx_enc_status_changed_phys(start, end, enc); +} + void __init tdx_early_init(void) { u64 cc_mask; diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index 956ced04c3be..97534c334473 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -81,5 +81,7 @@ struct tdx_module_output { u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, struct tdx_module_output *out); +void tdx_accept_memory(phys_addr_t start, phys_addr_t end); + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_SHARED_TDX_H */ diff --git a/arch/x86/mm/unaccepted_memory.c b/arch/x86/mm/unaccepted_memory.c index 05e216716690..9ec2304272dc 100644 --- a/arch/x86/mm/unaccepted_memory.c +++ b/arch/x86/mm/unaccepted_memory.c @@ -7,6 +7,7 @@ #include <asm/io.h> #include <asm/setup.h> +#include <asm/shared/tdx.h> #include <asm/unaccepted_memory.h> /* Protects unaccepted memory bitmap */ @@ -62,7 +63,13 @@ void accept_memory(phys_addr_t start, phys_addr_t end) unsigned long len = range_end - range_start; /* Platform-specific memory-acceptance call goes here */ - panic("Cannot accept memory: unknown platform\n"); + if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) { + tdx_accept_memory(range_start * PMD_SIZE, + range_end * PMD_SIZE); + } else { + panic("Cannot accept memory: unknown platform\n"); + } + bitmap_clear(bitmap, range_start, len); } spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
Hookup TDX-specific code to accept memory. Accepting the memory is the same process as converting memory from shared to private: kernel notifies VMM with MAP_GPA hypercall and then accept pages with ACCEPT_PAGE module call. The implementation in core kernel uses tdx_enc_status_changed(). It already used for converting memory to shared and back for I/O transactions. Boot stub provides own implementation of tdx_accept_memory(). It is similar in structure to tdx_enc_status_changed(), but only cares about converting memory to private. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- arch/x86/Kconfig | 1 + arch/x86/boot/compressed/mem.c | 27 ++++++++++- arch/x86/boot/compressed/tdx.c | 78 +++++++++++++++++++++++++++++++ arch/x86/coco/tdx/tdx.c | 30 ++++++++---- arch/x86/include/asm/shared/tdx.h | 2 + arch/x86/mm/unaccepted_memory.c | 9 +++- 6 files changed, 136 insertions(+), 11 deletions(-)