RE: [PATCH V4 03/13] x86/hyperv: Add new hvcall guest address host visibility support
From: Michael Kelley <hidden>
Date: 2021-09-02 00:16:42
Also in:
linux-arch, linux-iommu, linux-scsi, lkml, netdev, xen-devel
From: Tianyu Lan <redacted> Sent: Friday, August 27, 2021 10:21 AM
quoted hunk ↗ jump to hunk
Add new hvcall guest address host visibility support to mark memory visible to host. Call it inside set_memory_decrypted /encrypted(). Add HYPERVISOR feature check in the hv_is_isolation_supported() to optimize in non-virtualization environment. Acked-by: Dave Hansen <redacted> Signed-off-by: Tianyu Lan <redacted> --- Change since v3: * Fix error code handle in the __hv_set_mem_host_visibility(). * Move HvCallModifySparseGpaPageHostVisibility near to enum hv_mem_host_visibility. Change since v2: * Rework __set_memory_enc_dec() and call Hyper-V and AMD function according to platform check. Change since v1: * Use new staic call x86_set_memory_enc to avoid add Hyper-V specific check in the set_memory code. --- arch/x86/hyperv/Makefile | 2 +- arch/x86/hyperv/hv_init.c | 6 ++ arch/x86/hyperv/ivm.c | 113 +++++++++++++++++++++++++++++ arch/x86/include/asm/hyperv-tlfs.h | 17 +++++ arch/x86/include/asm/mshyperv.h | 4 +- arch/x86/mm/pat/set_memory.c | 19 +++-- include/asm-generic/hyperv-tlfs.h | 1 + include/asm-generic/mshyperv.h | 1 + 8 files changed, 156 insertions(+), 7 deletions(-) create mode 100644 arch/x86/hyperv/ivm.cdiff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile index 48e2c51464e8..5d2de10809ae 100644 --- a/arch/x86/hyperv/Makefile +++ b/arch/x86/hyperv/Makefile@@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-y := hv_init.o mmu.o nested.o irqdomain.o +obj-y := hv_init.o mmu.o nested.o irqdomain.o ivm.o obj-$(CONFIG_X86_64) += hv_apic.o hv_proc.o ifdef CONFIG_X86_64diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index eba10ed4f73e..b1aa42f60faa 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c@@ -603,6 +603,12 @@ EXPORT_SYMBOL_GPL(hv_get_isolation_type); bool hv_is_isolation_supported(void) { + if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) + return 0;
Use "return false" per previous comment from Wei Liu.
+ + if (!hypervisor_is_type(X86_HYPER_MS_HYPERV)) + return 0;
Use "return false".
quoted hunk ↗ jump to hunk
+ return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE; }diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c new file mode 100644 index 000000000000..a069c788ce3c --- /dev/null +++ b/arch/x86/hyperv/ivm.c@@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Hyper-V Isolation VM interface with paravisor and hypervisor + * + * Author: + * Tianyu Lan <Tianyu.Lan@microsoft.com> + */ + +#include <linux/hyperv.h> +#include <linux/types.h> +#include <linux/bitfield.h> +#include <linux/slab.h> +#include <asm/io.h> +#include <asm/mshyperv.h> + +/* + * hv_mark_gpa_visibility - Set pages visible to host via hvcall. + * + * In Isolation VM, all guest memory is encripted from host and guest
s/encripted/encrypted/
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host.
+ */
+int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
+ enum hv_mem_host_visibility visibility)
+{
+ struct hv_gpa_range_for_visibility **input_pcpu, *input;
+ u16 pages_processed;
+ u64 hv_status;
+ unsigned long flags;
+
+ /* no-op if partition isolation is not enabled */
+ if (!hv_is_isolation_supported())
+ return 0;
+
+ if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
+ pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
+ HV_MAX_MODIFY_GPA_REP_COUNT);
+ return -EINVAL;
+ }
+
+ local_irq_save(flags);
+ input_pcpu = (struct hv_gpa_range_for_visibility **)
+ this_cpu_ptr(hyperv_pcpu_input_arg);
+ input = *input_pcpu;
+ if (unlikely(!input)) {
+ local_irq_restore(flags);
+ return -EINVAL;
+ }
+
+ input->partition_id = HV_PARTITION_ID_SELF;
+ input->host_visibility = visibility;
+ input->reserved0 = 0;
+ input->reserved1 = 0;
+ memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
+ hv_status = hv_do_rep_hypercall(
+ HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
+ 0, input, &pages_processed);
+ local_irq_restore(flags);
+
+ if (hv_result_success(hv_status))
+ return 0;
+ else
+ return -EFAULT;
+}
+EXPORT_SYMBOL(hv_mark_gpa_visibility);In later comments on Patch 7 of this series, I have suggested that code in that patch should not call hv_mark_gpa_visibility() directly, but instead should call set_memory_encrypted() and set_memory_decrypted(). I'm thinking that those functions should be the standard way to change the visibility of pages in the Isolated VM case. Then hv_mark_gpa_visibility() could be static and it would not need a stub version for ARM64. It would only be called by __hv_set_mem_host_visibility below, and in turn by set_memory_encrypted()/decrypted().
+
+static int __hv_set_mem_host_visibility(void *kbuffer, int pagecount,
+ enum hv_mem_host_visibility visibility)
+{
+ u64 *pfn_array;
+ int ret = 0;
+ int i, pfn;
+
+ if (!hv_is_isolation_supported() || !hv_hypercall_pg)
+ return 0;
+
+ pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+ if (!pfn_array)
+ return -ENOMEM;
+
+ for (i = 0, pfn = 0; i < pagecount; i++) {
+ pfn_array[pfn] = virt_to_hvpfn(kbuffer + i * HV_HYP_PAGE_SIZE);
+ pfn++;
+
+ if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
+ ret = hv_mark_gpa_visibility(pfn, pfn_array,
+ visibility);
+ if (ret)
+ goto err_free_pfn_array;
+ pfn = 0;
+ }
+ }
+
+ err_free_pfn_array:
+ kfree(pfn_array);
+ return ret;
+}
+
+/*
+ * hv_set_mem_host_visibility - Set specified memory visible to host.
+ *
+ * In Isolation VM, all guest memory is encrypted from host and guest
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host. This function works as wrap of hv_mark_gpa_visibility()
+ * with memory base and size.
+ */
+int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible)
+{
+ enum hv_mem_host_visibility visibility = visible ?
+ VMBUS_PAGE_VISIBLE_READ_WRITE : VMBUS_PAGE_NOT_VISIBLE;
+
+ return __hv_set_mem_host_visibility((void *)addr, numpages, visibility);
+}Is there a need for this wrapper function? Couldn't the handling of the host visibility enum be folded into __hv_set_mem_host_visibility() and the initial double underscore dropped? Maybe I missed it, but I don't see that __hv_set_mem_host_visibility() is called anyplace else. Just trying to avoid complexity if it isn't really needed.
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 2322d6bd5883..381e88122a5f 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h@@ -276,6 +276,23 @@ enum hv_isolation_type { #define HV_X64_MSR_TIME_REF_COUNT HV_REGISTER_TIME_REF_COUNT #define HV_X64_MSR_REFERENCE_TSC HV_REGISTER_REFERENCE_TSC +/* Hyper-V memory host visibility */ +enum hv_mem_host_visibility { + VMBUS_PAGE_NOT_VISIBLE = 0, + VMBUS_PAGE_VISIBLE_READ_ONLY = 1, + VMBUS_PAGE_VISIBLE_READ_WRITE = 3 +}; + +/* HvCallModifySparseGpaPageHostVisibility hypercall */ +#define HV_MAX_MODIFY_GPA_REP_COUNT ((PAGE_SIZE / sizeof(u64)) - 2) +struct hv_gpa_range_for_visibility { + u64 partition_id; + u32 host_visibility:2; + u32 reserved0:30; + u32 reserved1; + u64 gpa_page_list[HV_MAX_MODIFY_GPA_REP_COUNT]; +} __packed; + /* * Declare the MSR used to setup pages used to communicate with the hypervisor. */diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 37739a277ac6..ffb2af079c6b 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h@@ -192,7 +192,9 @@ struct irq_domain *hv_create_pci_msi_domain(void); int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector, struct hv_interrupt_entry *entry); int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry); - +int hv_mark_gpa_visibility(u16 count, const u64 pfn[], + enum hv_mem_host_visibility visibility); +int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible); #else /* CONFIG_HYPERV */ static inline void hyperv_init(void) {} static inline void hyperv_setup_mmu_ops(void) {}diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index ad8a5c586a35..1e4a0882820a 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c@@ -29,6 +29,8 @@ #include <asm/proto.h> #include <asm/memtype.h> #include <asm/set_memory.h> +#include <asm/hyperv-tlfs.h> +#include <asm/mshyperv.h> #include "../mm_internal.h"@@ -1980,15 +1982,11 @@ int set_memory_global(unsigned long addr, int numpages) __pgprot(_PAGE_GLOBAL), 0); } -static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) +static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) { struct cpa_data cpa; int ret; - /* Nothing to do if memory encryption is not active */ - if (!mem_encrypt_active()) - return 0; - /* Should not be working on unaligned addresses */ if (WARN_ONCE(addr & ~PAGE_MASK, "misaligned address: %#lx\n", addr)) addr &= PAGE_MASK;@@ -2023,6 +2021,17 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) return ret; } +static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc) +{ + if (hv_is_isolation_supported()) + return hv_set_mem_host_visibility(addr, numpages, !enc); + + if (mem_encrypt_active()) + return __set_memory_enc_pgtable(addr, numpages, enc); + + return 0; +} + int set_memory_encrypted(unsigned long addr, int numpages) { return __set_memory_enc_dec(addr, numpages, true);diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h index 56348a541c50..8ed6733d5146 100644 --- a/include/asm-generic/hyperv-tlfs.h +++ b/include/asm-generic/hyperv-tlfs.h@@ -158,6 +158,7 @@ struct ms_hyperv_tsc_page { #define HVCALL_RETARGET_INTERRUPT 0x007e #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0 +#define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db /* Extended hypercalls */ #define HV_EXT_CALL_QUERY_CAPABILITIES 0x8001diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index 7537ae1db828..aa55447b9700 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h@@ -254,6 +254,7 @@ bool hv_query_ext_cap(u64 cap_query); static inline bool hv_is_hyperv_initialized(void) { return false; } static inline bool hv_is_hibernation_supported(void) { return false; } static inline void hyperv_cleanup(void) {} +static inline hv_is_isolation_supported(void); #endif /* CONFIG_HYPERV */ #endif --2.25.1