[RFC PATCH V5 08/15] x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest

Tianyu Lan
2023-05-01T08:58:32Z

From: Tianyu Lan <tiala@microsoft.com>

Read processor amd memory info from specific address which are
populated by Hyper-V. Initialize smp cpu related ops, pvalidate
system memory and add it into e820 table.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFCv4:
* Add mem info addr to get mem layout info
---
arch/x86/hyperv/ivm.c | 86 +++++++++++++++++++++++++++++++++
arch/x86/include/asm/mshyperv.h | 17 +++++++
arch/x86/kernel/cpu/mshyperv.c | 3 ++
3 files changed, 106 insertions(+)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 368b2731950e..522eab55c0dd 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -17,6 +17,11 @@
#include <asm/mem_encrypt.h>
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
+#include <asm/coco.h>
+#include <asm/io_apic.h>
+#include <asm/sev.h>
+#include <asm/realmode.h>
+#include <asm/e820/api.h>

#ifdef CONFIG_AMD_MEM_ENCRYPT

@@ -57,6 +62,8 @@ union hv_ghcb {

static u16 hv_ghcb_version __ro_after_init;

+static u32 processor_count;
+
u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
{
union hv_ghcb *hv_ghcb;
@@ -356,6 +363,85 @@ static bool hv_is_private_mmio(u64 addr)
return false;
}

+static __init void hv_snp_get_smp_config(unsigned int early)
+{
+ if (!early)
+ return;
+ /*
+ * There is no firmware and ACPI MADT table spport in
+ * in the Hyper-V SEV-SNP enlightened guest. Set smp
+ * related config variable during early stage.
+ */
+ while (num_processors < processor_count) {
+ early_per_cpu(x86_cpu_to_apicid, num_processors) = num_processors;
+ early_per_cpu(x86_bios_cpu_apicid, num_processors) = num_processors;
+ physid_set(num_processors, phys_cpu_present_map);
+ set_cpu_possible(num_processors, true);
+ set_cpu_present(num_processors, true);
+ num_processors++;
+ }
+}
+
+__init void hv_sev_init_mem_and_cpu(void)
+{
+ struct memory_map_entry *entry;
+ struct e820_entry *e820_entry;
+ u64 e820_end;
+ u64 ram_end;
+ u64 page;
+
+ /*
+ * Hyper-V enlightened snp guest boots kernel
+ * directly without bootloader and so roms,
+ * bios regions and reserve resources are not
+ * available. Set these callback to NULL.
+ */
+ x86_platform.legacy.rtc = 0;
+ x86_platform.legacy.reserve_bios_regions = 0;
+ x86_platform.set_wallclock = set_rtc_noop;
+ x86_platform.get_wallclock = get_rtc_noop;
+ x86_init.resources.probe_roms = x86_init_noop;
+ x86_init.resources.reserve_resources = x86_init_noop;
+ x86_init.mpparse.find_smp_config = x86_init_noop;
+ x86_init.mpparse.get_smp_config = hv_snp_get_smp_config;
+
+ /*
+ * Hyper-V SEV-SNP enlightened guest doesn't support ioapic
+ * and legacy APIC page read/write. Switch to hv apic here.
+ */
+ disable_ioapic_support();
+
+ /* Get processor and mem info. */
+ processor_count = *(u32 *)__va(EN_SEV_SNP_PROCESSOR_INFO_ADDR);
+ entry = (struct memory_map_entry *)__va(EN_SEV_SNP_MEM_INFO_ADDR);
+
+ /*
+ * There is no bootloader/EFI firmware in the SEV SNP guest.
+ * E820 table in the memory just describes memory for kernel,
+ * ACPI table, cmdline, boot params and ramdisk. The dynamic
+ * data(e.g, vcpu nnumber and the rest memory layout) needs to
+ * be read from EN_SEV_SNP_PROCESSOR_INFO_ADDR.
+ */
+ for (; entry->numpages != 0; entry++) {
+ e820_entry = &e820_table->entries[
+ e820_table->nr_entries - 1];
+ e820_end = e820_entry->addr + e820_entry->size;
+ ram_end = (entry->starting_gpn +
+ entry->numpages) * PAGE_SIZE;
+
+ if (e820_end < entry->starting_gpn * PAGE_SIZE)
+ e820_end = entry->starting_gpn * PAGE_SIZE;
+
+ if (e820_end < ram_end) {
+ pr_info("Hyper-V: add e820 entry [mem %#018Lx-%#018Lx]\n", e820_end, ram_end - 1);
+ e820__range_add(e820_end, ram_end - e820_end,
+ E820_TYPE_RAM);
+ for (page = e820_end; page < ram_end; page += PAGE_SIZE)
+ pvalidate((unsigned long)__va(page), RMP_PG_SIZE_4K, true);
+ }
+ }
+}
+
void __init hv_vtom_init(void)
{
/*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 939373791249..84e024ffacd5 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -50,6 +50,21 @@ extern bool hv_isolation_type_en_snp(void);

extern union hv_ghcb * __percpu *hv_ghcb_pg;

+/*
+ * Hyper-V puts processor and memory layout info
+ * to this address in SEV-SNP enlightened guest.
+ */
+#define EN_SEV_SNP_PROCESSOR_INFO_ADDR 0x802000
+#define EN_SEV_SNP_MEM_INFO_ADDR 0x802018
+
+struct memory_map_entry {
+ u64 starting_gpn;
+ u64 numpages;
+ u16 type;
+ u16 flags;
+ u32 reserved;
+};
+
int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
@@ -255,12 +270,14 @@ void hv_ghcb_msr_read(u64 msr, u64 *value);
bool hv_ghcb_negotiate_protocol(void);
void hv_ghcb_terminate(unsigned int set, unsigned int reason);
void hv_vtom_init(void);
+void hv_sev_init_mem_and_cpu(void);
#else
static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
static inline void hv_vtom_init(void) {}
+static inline void hv_sev_init_mem_and_cpu(void) {}
#endif

extern bool hv_isolation_type_snp(void);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 63a2bfbfe701..dea9b881180b 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -529,6 +529,9 @@ static void __init ms_hyperv_init_platform(void)
if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
mark_tsc_unstable("running on Hyper-V");

+ if (hv_isolation_type_en_snp())
+ hv_sev_init_mem_and_cpu();
+
hardlockup_detector_disable();
}

--
2.25.1