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@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-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,
Jason@zx2c4.com, nik.borisov@suse.com, mikelley@microsoft.com
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, Tianyu.Lan@microsoft.com,
rick.p.edgecombe@intel.com, andavis@redhat.com,
mheslin@redhat.com, vkuznets@redhat.com, xiaoyao.li@intel.com,
Dexuan Cui <decui@microsoft.com>
Subject: [PATCH v3 03/10] Drivers: hv: vmbus: Support fully enlightened TDX guests
Date: Thu, 24 Aug 2023 01:07:05 -0700 [thread overview]
Message-ID: <20230824080712.30327-4-decui@microsoft.com> (raw)
In-Reply-To: <20230824080712.30327-1-decui@microsoft.com>
Add Hyper-V specific code so that a fully enlightened TDX guest (i.e.
without the paravisor) can run on Hyper-V:
Don't use hv_vp_assist_page. Use GHCI instead.
Don't try to use the unsupported HV_REGISTER_CRASH_CTL.
Don't trust (use) Hyper-V's TLB-flushing hypercalls.
Don't use lazy EOI.
Share the SynIC Event/Message pages with the hypervisor.
Don't use the Hyper-V TSC page for now, because non-trivial work is
required to share the page with the hypervisor.
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
Changes in v2: None
Changes in v3:
ms_hyperv_init_platform(): Removed cc_mkdec(0).
hv_synic_alloc(), hv_synic_enable_regs():
Removed "|= ms_hyperv.shared_gpa_boundary": No longer needed on GA Hyper-V.
arch/x86/hyperv/hv_apic.c | 15 ++++++++++++---
arch/x86/hyperv/hv_init.c | 19 +++++++++++++++----
arch/x86/kernel/cpu/mshyperv.c | 14 ++++++++++++++
drivers/hv/hv.c | 9 +++++++--
4 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 1fbda2f94184..cb7429046d18 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -177,8 +177,11 @@ static bool __send_ipi_mask(const struct cpumask *mask, int vector,
(exclude_self && weight == 1 && cpumask_test_cpu(this_cpu, mask)))
return true;
- if (!hv_hypercall_pg)
- return false;
+ /* A fully enlightened TDX VM uses GHCI rather than hv_hypercall_pg. */
+ if (!hv_hypercall_pg) {
+ if (ms_hyperv.paravisor_present || !hv_isolation_type_tdx())
+ return false;
+ }
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return false;
@@ -231,9 +234,15 @@ static bool __send_ipi_one(int cpu, int vector)
trace_hyperv_send_ipi_one(cpu, vector);
- if (!hv_hypercall_pg || (vp == VP_INVAL))
+ if (vp == VP_INVAL)
return false;
+ /* A fully enlightened TDX VM uses GHCI rather than hv_hypercall_pg. */
+ if (!hv_hypercall_pg) {
+ if (ms_hyperv.paravisor_present || !hv_isolation_type_tdx())
+ return false;
+ }
+
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return false;
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 255e02ec467e..c1c1b4e1502f 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -80,7 +80,7 @@ static int hyperv_init_ghcb(void)
static int hv_cpu_init(unsigned int cpu)
{
union hv_vp_assist_msr_contents msr = { 0 };
- struct hv_vp_assist_page **hvp = &hv_vp_assist_page[cpu];
+ struct hv_vp_assist_page **hvp;
int ret;
ret = hv_common_cpu_init(cpu);
@@ -90,6 +90,7 @@ static int hv_cpu_init(unsigned int cpu)
if (!hv_vp_assist_page)
return 0;
+ hvp = &hv_vp_assist_page[cpu];
if (hv_root_partition) {
/*
* For root partition we get the hypervisor provided VP assist
@@ -442,11 +443,21 @@ void __init hyperv_init(void)
if (hv_common_init())
return;
- hv_vp_assist_page = kcalloc(num_possible_cpus(),
- sizeof(*hv_vp_assist_page), GFP_KERNEL);
+ /*
+ * The VP assist page is useless to a TDX guest: the only use we
+ * would have for it is lazy EOI, which can not be used with TDX.
+ */
+ if (hv_isolation_type_tdx())
+ hv_vp_assist_page = NULL;
+ else
+ hv_vp_assist_page = kcalloc(num_possible_cpus(),
+ sizeof(*hv_vp_assist_page),
+ GFP_KERNEL);
if (!hv_vp_assist_page) {
ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
- goto common_free;
+
+ if (!hv_isolation_type_tdx())
+ goto common_free;
}
if (hv_isolation_type_snp()) {
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 63093870ec33..ff3d9c5de19c 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -420,6 +420,20 @@ static void __init ms_hyperv_init_platform(void)
static_branch_enable(&isolation_type_en_snp);
} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX) {
static_branch_enable(&isolation_type_tdx);
+
+ /* A TDX VM must use x2APIC and doesn't use lazy EOI. */
+ ms_hyperv.hints &= ~HV_X64_APIC_ACCESS_RECOMMENDED;
+
+ if (!ms_hyperv.paravisor_present) {
+ /* To be supported: more work is required. */
+ ms_hyperv.features &= ~HV_MSR_REFERENCE_TSC_AVAILABLE;
+
+ /* HV_REGISTER_CRASH_CTL is unsupported. */
+ ms_hyperv.misc_features &= ~HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
+
+ /* Don't trust Hyper-V's TLB-flushing hypercalls. */
+ ms_hyperv.hints &= ~HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED;
+ }
}
}
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index ec6e35a0d9bf..d1064118a72f 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -121,11 +121,15 @@ int hv_synic_alloc(void)
(void *)get_zeroed_page(GFP_ATOMIC);
if (hv_cpu->synic_event_page == NULL) {
pr_err("Unable to allocate SYNIC event page\n");
+
+ free_page((unsigned long)hv_cpu->synic_message_page);
+ hv_cpu->synic_message_page = NULL;
goto err;
}
}
- if (hv_isolation_type_en_snp()) {
+ if (!ms_hyperv.paravisor_present &&
+ (hv_isolation_type_en_snp() || hv_isolation_type_tdx())) {
ret = set_memory_decrypted((unsigned long)
hv_cpu->synic_message_page, 1);
if (ret) {
@@ -174,7 +178,8 @@ void hv_synic_free(void)
= per_cpu_ptr(hv_context.cpu_context, cpu);
/* It's better to leak the page if the encryption fails. */
- if (hv_isolation_type_en_snp()) {
+ if (!ms_hyperv.paravisor_present &&
+ (hv_isolation_type_en_snp() || hv_isolation_type_tdx())) {
if (hv_cpu->synic_message_page) {
ret = set_memory_encrypted((unsigned long)
hv_cpu->synic_message_page, 1);
--
2.25.1
next prev parent reply other threads:[~2023-08-24 8:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-24 8:07 [PATCH v3 00/10] Support TDX guests on Hyper-V (the Hyper-V specific part) Dexuan Cui
2023-08-24 8:07 ` [PATCH v3 01/10] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests Dexuan Cui
2023-08-24 8:07 ` [PATCH v3 02/10] x86/hyperv: Support hypercalls for fully enlightened " Dexuan Cui
2023-08-24 8:07 ` Dexuan Cui [this message]
2023-08-24 8:07 ` [PATCH v3 04/10] x86/hyperv: Fix serial console interrupts " Dexuan Cui
2023-08-24 8:07 ` [PATCH v3 05/10] Drivers: hv: vmbus: Support >64 VPs for a fully enlightened TDX/SNP VM Dexuan Cui
2023-08-24 8:07 ` [PATCH v3 06/10] x86/hyperv: Introduce a global variable hyperv_paravisor_present Dexuan Cui
2023-08-24 14:06 ` Michael Kelley (LINUX)
2023-08-24 14:41 ` Tianyu Lan
2023-08-24 8:07 ` [PATCH v3 07/10] Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor Dexuan Cui
2023-08-24 14:07 ` Michael Kelley (LINUX)
2023-08-24 14:40 ` Tianyu Lan
2023-08-24 8:07 ` [PATCH v3 08/10] x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM " Dexuan Cui
2023-08-24 14:08 ` Michael Kelley (LINUX)
2023-08-24 14:44 ` Tianyu Lan
2023-12-04 15:10 ` Dave Hansen
2024-01-17 2:22 ` Wei Liu
2023-08-24 8:07 ` [PATCH v3 09/10] x86/hyperv: Remove hv_isolation_type_en_snp Dexuan Cui
2023-08-24 14:09 ` Michael Kelley (LINUX)
2023-08-24 14:45 ` Tianyu Lan
2023-08-24 8:07 ` [PATCH v3 10/10] x86/hyperv: Move the code in ivm.c around to avoid unnecessary ifdef's Dexuan Cui
2023-08-24 14:10 ` Michael Kelley (LINUX)
2023-08-24 14:46 ` Tianyu Lan
2023-08-25 0:05 ` [PATCH v3 00/10] Support TDX guests on Hyper-V (the Hyper-V specific part) Wei Liu
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