[PATCH 5/5] x86/tdx: Unaccepted memory support

Kirill A. Shutemov
2021-08-10T06:26:49Z

All preparation is complete. Hookup TDX-specific code to accept memory.

There are two tdg_accept_memory() implementations: one in main kernel
and one in the decompresser.

The implementation in core kernel uses tdx_hcall_gpa_intent(). The
helper is not available in the decompresser, self-contained
implementation added there instead.

Note that tdx_hcall_gpa_intent() is going to be more complex once we
teach it to accept in 1G and 2M chunks.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/Kconfig | 1 +
arch/x86/boot/compressed/tdx.c | 29 ++++++++++++++++++++
arch/x86/boot/compressed/unaccepted_memory.c | 5 +++-
arch/x86/include/asm/tdx.h | 2 ++
arch/x86/kernel/tdx.c | 8 ++++++
arch/x86/mm/unaccepted_memory.c | 6 +++-
6 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c0261cc72449..5b1b3dc84c7d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -874,6 +874,7 @@ config INTEL_TDX_GUEST
select ARCH_HAS_PROTECTED_GUEST
select X86_MEM_ENCRYPT_COMMON
select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+ select UNACCEPTED_MEMORY
help
Provide support for running in a trusted domain on Intel processors
equipped with Trusted Domain eXtensions. TDX is a new Intel
diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c
index 88ed6465405b..6f13bdaf327f 100644
--- a/arch/x86/boot/compressed/tdx.c
+++ b/arch/x86/boot/compressed/tdx.c
@@ -5,6 +5,10 @@

#include "../cpuflags.h"
#include "../string.h"
+#include "error.h"
+
+#include <asm/page_types.h>
+#include <asm/tdx.h>

#define TDX_CPUID_LEAF_ID 0x21

@@ -32,3 +36,28 @@ bool early_is_tdx_guest(void)

return !!tdx_guest;
}
+
+#define TDACCEPTPAGE 6
+#define TDVMCALL_MAP_GPA 0x10001
+
+void tdg_accept_memory(phys_addr_t start, phys_addr_t end)
+{
+ struct tdx_hypercall_output outl = {0};
+ int i;
+
+ if (__tdx_hypercall(TDX_HYPERCALL_STANDARD, TDVMCALL_MAP_GPA,
+ start, end, 0, 0, &outl)) {
+ error("Cannot accept memory: MapGPA failed\n");
+ }
+
+ /*
+ * For shared->private conversion, accept the page using TDACCEPTPAGE
+ * TDX module call.
+ */
+ for (i = 0; i < (end - start) / PAGE_SIZE; i++) {
+ if (__tdx_module_call(TDACCEPTPAGE, start + i * PAGE_SIZE,
+ 0, 0, 0, NULL)) {
+ error("Cannot accept memory: page accept failed\n");
+ }
+ }
+}
diff --git a/arch/x86/boot/compressed/unaccepted_memory.c b/arch/x86/boot/compressed/unaccepted_memory.c
index 818d32169eef..146a3a6968a8 100644
--- a/arch/x86/boot/compressed/unaccepted_memory.c
+++ b/arch/x86/boot/compressed/unaccepted_memory.c
@@ -4,7 +4,10 @@
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 (early_is_tdx_guest())
+ tdg_accept_memory(start, end);
+ else
+ error("Cannot accept memory");
}

void mark_unaccepted(struct boot_params *params, u64 start, u64 num)
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index af6e4cd8078d..f74b6cfde205 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -97,6 +97,8 @@ extern phys_addr_t tdg_shared_mask(void);
extern int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
enum tdx_map_type map_type);

+extern void tdg_accept_memory(phys_addr_t start, phys_addr_t end);
+
int tdx_mcall_tdreport(u64 data, u64 reportdata);

int tdx_mcall_rtmr_extend(u64 data, u64 rmtr);
diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c
index dc6d9441f3be..75f3804f86da 100644
--- a/arch/x86/kernel/tdx.c
+++ b/arch/x86/kernel/tdx.c
@@ -372,6 +372,14 @@ int tdx_hcall_gpa_intent(phys_addr_t gpa, int numpages,
return 0;
}

+void tdg_accept_memory(phys_addr_t start, phys_addr_t end)
+{
+ if (tdx_hcall_gpa_intent(start, (end - start) / PAGE_SIZE,
+ TDX_MAP_PRIVATE)) {
+ panic("Accepting memory failed\n");
+ }
+}
+
static __cpuidle void tdg_halt(void)
{
u64 ret;
diff --git a/arch/x86/mm/unaccepted_memory.c b/arch/x86/mm/unaccepted_memory.c
index e11933f62ead..19e0309e128b 100644
--- a/arch/x86/mm/unaccepted_memory.c
+++ b/arch/x86/mm/unaccepted_memory.c
@@ -5,6 +5,7 @@

#include <asm/io.h>
#include <asm/setup.h>
+#include <asm/tdx.h>
#include <asm/unaccepted_memory.h>

static DEFINE_SPINLOCK(unaccepted_memory_lock);
@@ -21,7 +22,10 @@ static void __accept_memory(phys_addr_t start, phys_addr_t end)
start / PMD_SIZE,
DIV_ROUND_UP(end, PMD_SIZE)) {
/* Platform-specific memory-acceptance call goes here */
- panic("Cannot accept memory");
+ if (prot_guest_has(PATTR_GUEST_TDX))
+ tdg_accept_memory(rs * PMD_SIZE, re * PMD_SIZE);
+ else
+ panic("Cannot accept memory");
bitmap_clear(unaccepted_memory, rs, re - rs);
}
}
--
2.31.1