From: Dexuan Cui <decui@microsoft.com>
To: ak@linux.intel.com, arnd@arndb.de, bp@alien8.de,
brijesh.singh@amd.com, dan.j.williams@intel.com,
dave.hansen@linux.intel.com, haiyangz@microsoft.com,
hpa@zytor.com, jane.chu@oracle.com,
kirill.shutemov@linux.intel.com, kys@microsoft.com,
linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
luto@kernel.org, mingo@redhat.com, peterz@infradead.org,
rostedt@goodmis.org, sathyanarayanan.kuppuswamy@linux.intel.com,
seanjc@google.com, tglx@linutronix.de, tony.luck@intel.com,
wei.liu@kernel.org, x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Dexuan Cui <decui@microsoft.com>
Subject: [PATCH 2/6] x86/tdx: Retry TDVMCALL_MAP_GPA() when needed
Date: Mon, 21 Nov 2022 11:51:47 -0800 [thread overview]
Message-ID: <20221121195151.21812-3-decui@microsoft.com> (raw)
In-Reply-To: <20221121195151.21812-1-decui@microsoft.com>
GHCI spec for TDX 1.0 says that the MapGPA call may fail with the R10
error code = TDG.VP.VMCALL_RETRY (1), and the guest must retry this
operation for the pages in the region starting at the GPA specified
in R11.
When a TDX guest runs on Hyper-V, Hyper-V returns the retry error
when hyperv_init() -> swiotlb_update_mem_attributes() ->
set_memory_decrypted() decrypts up to 1GB of swiotlb bounce buffers.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
arch/x86/coco/tdx/tdx.c | 65 +++++++++++++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 6 deletions(-)
diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 3fee96931ff5..46971cc7d006 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -20,6 +20,8 @@
/* TDX hypercall Leaf IDs */
#define TDVMCALL_MAP_GPA 0x10001
+#define TDVMCALL_STATUS_RETRY 1
+
/* MMIO direction */
#define EPT_READ 0
#define EPT_WRITE 1
@@ -52,6 +54,25 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
return __tdx_hypercall(&args, 0);
}
+static inline u64 _tdx_hypercall_output_r11(u64 fn, u64 r12, u64 r13, u64 r14,
+ u64 r15, u64 *r11)
+{
+ struct tdx_hypercall_args args = {
+ .r10 = TDX_HYPERCALL_STANDARD,
+ .r11 = fn,
+ .r12 = r12,
+ .r13 = r13,
+ .r14 = r14,
+ .r15 = r15,
+ };
+
+ u64 ret;
+
+ ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+ *r11 = args.r11;
+ return ret;
+}
+
/* Called from __tdx_hypercall() for unrecoverable failure */
void __tdx_hypercall_failed(void)
{
@@ -691,6 +712,43 @@ static bool try_accept_one(phys_addr_t *start, unsigned long len,
return true;
}
+/*
+ * 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>"
+ */
+static bool tdx_map_gpa(phys_addr_t start, phys_addr_t end, bool enc)
+{
+ u64 ret, r11;
+
+ while (1) {
+ ret = _tdx_hypercall_output_r11(TDVMCALL_MAP_GPA, start,
+ end - start, 0, 0, &r11);
+ if (!ret)
+ break;
+
+ if (ret != TDVMCALL_STATUS_RETRY)
+ break;
+
+ /*
+ * The guest must retry the operation for the pages in the
+ * region starting at the GPA specified in R11. Make sure R11
+ * contains a sane value.
+ */
+ if ((r11 & ~cc_mkdec(0)) < (start & ~cc_mkdec(0)) ||
+ (r11 & ~cc_mkdec(0)) >= (end & ~cc_mkdec(0)))
+ return false;
+
+ start = r11;
+
+ /* Set the shared (decrypted) bit. */
+ if (!enc)
+ start |= cc_mkdec(0);
+ }
+
+ return !ret;
+}
+
/*
* 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
@@ -707,12 +765,7 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
end |= cc_mkdec(0);
}
- /*
- * 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))
+ if (!tdx_map_gpa(start, end, enc))
return false;
/* private->shared conversion requires only MapGPA call */
--
2.25.1
next prev parent reply other threads:[~2022-11-21 19:53 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-21 19:51 [PATCH 0/6] Support TDX guests on Hyper-V Dexuan Cui
2022-11-21 19:51 ` [PATCH 1/6] x86/tdx: Support hypercalls for " Dexuan Cui
2022-11-21 20:38 ` Dave Hansen
2022-11-21 23:52 ` Kirill A. Shutemov
2022-11-23 1:37 ` Dexuan Cui
2022-11-23 1:56 ` Dexuan Cui
2022-11-23 16:04 ` Dave Hansen
2022-11-23 18:59 ` Dexuan Cui
2022-11-23 3:52 ` Sathyanarayanan Kuppuswamy
2022-11-23 14:40 ` Kirill A. Shutemov
2022-11-23 18:55 ` Dexuan Cui
2022-11-30 19:14 ` Dexuan Cui
2022-12-02 21:47 ` 'Kirill A. Shutemov'
2022-11-23 16:03 ` Dave Hansen
2022-11-21 19:51 ` Dexuan Cui [this message]
2022-11-21 20:55 ` [PATCH 2/6] x86/tdx: Retry TDVMCALL_MAP_GPA() when needed Dave Hansen
2022-11-23 2:55 ` Dexuan Cui
2022-11-22 0:01 ` Kirill A. Shutemov
2022-11-23 3:27 ` Dexuan Cui
2022-11-23 13:30 ` Michael Kelley (LINUX)
2022-11-28 0:07 ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 3/6] x86/tdx: Support vmalloc() for tdx_enc_status_changed() Dexuan Cui
2022-11-21 21:00 ` Dave Hansen
2022-11-23 4:01 ` Dexuan Cui
2022-11-22 0:24 ` Kirill A. Shutemov
2022-11-23 23:51 ` Dexuan Cui
2022-11-24 7:51 ` Kirill A. Shutemov
2022-11-27 20:27 ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 4/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests Dexuan Cui
2022-11-21 21:01 ` Dave Hansen
2022-11-21 21:48 ` Borislav Petkov
2022-11-22 0:32 ` Sathyanarayanan Kuppuswamy
2022-11-23 19:13 ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 5/6] x86/hyperv: Support hypercalls for " Dexuan Cui
2022-11-21 20:05 ` Dave Hansen
2022-11-23 2:14 ` Dexuan Cui
2022-11-23 14:47 ` Kirill A. Shutemov
2022-11-23 18:13 ` Dexuan Cui
2022-11-23 18:18 ` Sathyanarayanan Kuppuswamy
2022-11-23 19:07 ` Dexuan Cui
2022-11-23 14:45 ` Michael Kelley (LINUX)
2022-11-28 0:58 ` Dexuan Cui
2022-11-28 1:20 ` Michael Kelley (LINUX)
2022-11-28 1:36 ` Dexuan Cui
2022-11-28 1:21 ` Sathyanarayanan Kuppuswamy
2022-11-28 1:55 ` Dexuan Cui
2022-11-28 15:22 ` Dave Hansen
2022-11-28 19:03 ` Dexuan Cui
2022-11-28 19:11 ` Dave Hansen
2022-11-28 19:37 ` Dexuan Cui
2022-11-28 19:48 ` Dave Hansen
2022-11-28 20:36 ` Dexuan Cui
2022-11-28 21:15 ` Dave Hansen
2022-11-28 21:53 ` Dexuan Cui
2022-11-21 19:51 ` [PATCH 6/6] Drivers: hv: vmbus: Support " Dexuan Cui
2023-01-06 11:00 ` Zhi Wang
2023-01-09 6:59 ` Dexuan Cui
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