[PATCH v8 07/20] virt: geniezone: Optimize performance of protected VM memory
Yi-De Wu
yi-de.wu at mediatek.com
Thu Dec 28 02:51:34 PST 2023
From: "Yingshiuan Pan" <yingshiuan.pan at mediatek.com>
The memory protection mechanism performs better with batch operations on
memory pages. To leverage this, we pre-allocate memory for VMs that are
set to protected mode. As a result, the memory protection mechanism can
proactively protect the pre-allocated memory in advance through batch
operations, leading to improved performance during VM booting.
Signed-off-by: Yingshiuan Pan <yingshiuan.pan at mediatek.com>
Signed-off-by: Jerry Wang <ze-yu.wang at mediatek.com>
Signed-off-by: Liju Chen <liju-clr.chen at mediatek.com>
Signed-off-by: Yi-De Wu <yi-de.wu at mediatek.com>
---
arch/arm64/geniezone/vm.c | 146 ++++++++++++++++++++++++++++++
drivers/virt/geniezone/Makefile | 3 +-
drivers/virt/geniezone/gzvm_mmu.c | 108 ++++++++++++++++++++++
3 files changed, 256 insertions(+), 1 deletion(-)
create mode 100644 drivers/virt/geniezone/gzvm_mmu.c
diff --git a/arch/arm64/geniezone/vm.c b/arch/arm64/geniezone/vm.c
index 02f94c86fbf1..e669a63ccac3 100644
--- a/arch/arm64/geniezone/vm.c
+++ b/arch/arm64/geniezone/vm.c
@@ -156,6 +156,122 @@ static int gzvm_vm_ioctl_get_pvmfw_size(struct gzvm *gzvm,
return 0;
}
+/**
+ * fill_constituents() - Populate pa to buffer until full
+ * @consti: Pointer to struct mem_region_addr_range.
+ * @consti_cnt: Constituent count.
+ * @max_nr_consti: Maximum number of constituent count.
+ * @gfn: Guest frame number.
+ * @total_pages: Total page numbers.
+ * @slot: Pointer to struct gzvm_memslot.
+ *
+ * Return: how many pages we've fill in, negative if error
+ */
+static int fill_constituents(struct mem_region_addr_range *consti,
+ int *consti_cnt, int max_nr_consti, u64 gfn,
+ u32 total_pages, struct gzvm_memslot *slot)
+{
+ u64 pfn, prev_pfn, gfn_end;
+ int nr_pages = 1;
+ int i = 0;
+
+ if (unlikely(total_pages == 0))
+ return -EINVAL;
+ gfn_end = gfn + total_pages;
+
+ /* entry 0 */
+ if (gzvm_gfn_to_pfn_memslot(slot, gfn, &pfn) != 0)
+ return -EFAULT;
+ consti[0].address = PFN_PHYS(pfn);
+ consti[0].pg_cnt = 1;
+ gfn++;
+ prev_pfn = pfn;
+
+ while (i < max_nr_consti && gfn < gfn_end) {
+ if (gzvm_gfn_to_pfn_memslot(slot, gfn, &pfn) != 0)
+ return -EFAULT;
+ if (pfn == (prev_pfn + 1)) {
+ consti[i].pg_cnt++;
+ } else {
+ i++;
+ if (i >= max_nr_consti)
+ break;
+ consti[i].address = PFN_PHYS(pfn);
+ consti[i].pg_cnt = 1;
+ }
+ prev_pfn = pfn;
+ gfn++;
+ nr_pages++;
+ }
+ if (i != max_nr_consti)
+ i++;
+ *consti_cnt = i;
+
+ return nr_pages;
+}
+
+/**
+ * populate_mem_region() - Iterate all mem slot and populate pa to buffer until it's full
+ * @gzvm: Pointer to struct gzvm.
+ *
+ * Return: 0 if it is successful, negative if error
+ */
+static int populate_mem_region(struct gzvm *gzvm)
+{
+ int slot_cnt = 0;
+
+ while (slot_cnt < GZVM_MAX_MEM_REGION && gzvm->memslot[slot_cnt].npages != 0) {
+ struct gzvm_memslot *memslot = &gzvm->memslot[slot_cnt];
+ struct gzvm_memory_region_ranges *region;
+ int max_nr_consti, remain_pages;
+ u64 gfn, gfn_end;
+ u32 buf_size;
+
+ buf_size = PAGE_SIZE * 2;
+ region = alloc_pages_exact(buf_size, GFP_KERNEL);
+ if (!region)
+ return -ENOMEM;
+
+ max_nr_consti = (buf_size - sizeof(*region)) /
+ sizeof(struct mem_region_addr_range);
+
+ region->slot = memslot->slot_id;
+ remain_pages = memslot->npages;
+ gfn = memslot->base_gfn;
+ gfn_end = gfn + remain_pages;
+
+ while (gfn < gfn_end) {
+ int nr_pages;
+
+ nr_pages = fill_constituents(region->constituents,
+ ®ion->constituent_cnt,
+ max_nr_consti, gfn,
+ remain_pages, memslot);
+
+ if (nr_pages < 0) {
+ pr_err("Failed to fill constituents\n");
+ free_pages_exact(region, buf_size);
+ return -EFAULT;
+ }
+
+ region->gpa = PFN_PHYS(gfn);
+ region->total_pages = nr_pages;
+ remain_pages -= nr_pages;
+ gfn += nr_pages;
+
+ if (gzvm_arch_set_memregion(gzvm->vm_id, buf_size,
+ virt_to_phys(region))) {
+ pr_err("Failed to register memregion to hypervisor\n");
+ free_pages_exact(region, buf_size);
+ return -EFAULT;
+ }
+ }
+ free_pages_exact(region, buf_size);
+ ++slot_cnt;
+ }
+ return 0;
+}
+
/**
* gzvm_vm_ioctl_cap_pvm() - Proceed GZVM_CAP_PROTECTED_VM's subcommands
* @gzvm: Pointer to struct gzvm.
@@ -177,6 +293,11 @@ static int gzvm_vm_ioctl_cap_pvm(struct gzvm *gzvm,
case GZVM_CAP_PVM_SET_PVMFW_GPA:
fallthrough;
case GZVM_CAP_PVM_SET_PROTECTED_VM:
+ /*
+ * To improve performance for protected VM, we have to populate VM's memory
+ * before VM booting
+ */
+ populate_mem_region(gzvm);
ret = gzvm_vm_arch_enable_cap(gzvm, cap, &res);
return ret;
case GZVM_CAP_PVM_GET_PVMFW_SIZE:
@@ -205,3 +326,28 @@ int gzvm_vm_ioctl_arch_enable_cap(struct gzvm *gzvm,
return -EINVAL;
}
+
+/**
+ * gzvm_hva_to_pa_arch() - converts hva to pa with arch-specific way
+ * @hva: Host virtual address.
+ *
+ * Return: GZVM_PA_ERR_BAD for translation error
+ */
+u64 gzvm_hva_to_pa_arch(u64 hva)
+{
+ unsigned long flags;
+ u64 par;
+
+ local_irq_save(flags);
+ asm volatile("at s1e1r, %0" :: "r" (hva));
+ isb();
+ par = read_sysreg_par();
+ local_irq_restore(flags);
+
+ if (par & SYS_PAR_EL1_F)
+ return GZVM_PA_ERR_BAD;
+ par = par & PAR_PA47_MASK;
+ if (!par)
+ return GZVM_PA_ERR_BAD;
+ return par;
+}
diff --git a/drivers/virt/geniezone/Makefile b/drivers/virt/geniezone/Makefile
index 25614ea3dea2..59fc4510a843 100644
--- a/drivers/virt/geniezone/Makefile
+++ b/drivers/virt/geniezone/Makefile
@@ -6,4 +6,5 @@
GZVM_DIR ?= ../../../drivers/virt/geniezone
-gzvm-y := $(GZVM_DIR)/gzvm_main.o $(GZVM_DIR)/gzvm_vm.o
+gzvm-y := $(GZVM_DIR)/gzvm_main.o $(GZVM_DIR)/gzvm_vm.o \
+ $(GZVM_DIR)/gzvm_mmu.o
diff --git a/drivers/virt/geniezone/gzvm_mmu.c b/drivers/virt/geniezone/gzvm_mmu.c
new file mode 100644
index 000000000000..f24fa7e6d975
--- /dev/null
+++ b/drivers/virt/geniezone/gzvm_mmu.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 MediaTek Inc.
+ */
+
+#include <linux/gzvm_drv.h>
+
+/**
+ * hva_to_pa_fast() - converts hva to pa in generic fast way
+ * @hva: Host virtual address.
+ *
+ * Return: GZVM_PA_ERR_BAD for translation error
+ */
+u64 hva_to_pa_fast(u64 hva)
+{
+ struct page *page[1];
+ u64 pfn;
+
+ if (get_user_page_fast_only(hva, 0, page)) {
+ pfn = page_to_phys(page[0]);
+ put_page(page[0]);
+ return pfn;
+ }
+ return GZVM_PA_ERR_BAD;
+}
+
+/**
+ * hva_to_pa_slow() - converts hva to pa in a slow way
+ * @hva: Host virtual address
+ *
+ * This function converts HVA to PA in a slow way because the target hva is not
+ * yet allocated and mapped in the host stage1 page table, we cannot find it
+ * directly from current page table.
+ * Thus, we have to allocate it and this operation is much slower than directly
+ * find via current page table.
+ *
+ * Context: This function may sleep
+ * Return: PA or GZVM_PA_ERR_BAD for translation error
+ */
+u64 hva_to_pa_slow(u64 hva)
+{
+ struct page *page = NULL;
+ u64 pfn = 0;
+ int npages;
+
+ npages = get_user_pages_unlocked(hva, 1, &page, 0);
+ if (npages != 1)
+ return GZVM_PA_ERR_BAD;
+
+ if (page) {
+ pfn = page_to_phys(page);
+ put_page(page);
+ return pfn;
+ }
+
+ return GZVM_PA_ERR_BAD;
+}
+
+static u64 __gzvm_gfn_to_pfn_memslot(struct gzvm_memslot *memslot, u64 gfn)
+{
+ u64 hva, pa;
+
+ hva = gzvm_gfn_to_hva_memslot(memslot, gfn);
+
+ pa = gzvm_hva_to_pa_arch(hva);
+ if (pa != GZVM_PA_ERR_BAD)
+ return PHYS_PFN(pa);
+
+ pa = hva_to_pa_fast(hva);
+ if (pa != GZVM_PA_ERR_BAD)
+ return PHYS_PFN(pa);
+
+ pa = hva_to_pa_slow(hva);
+ if (pa != GZVM_PA_ERR_BAD)
+ return PHYS_PFN(pa);
+
+ return GZVM_PA_ERR_BAD;
+}
+
+/**
+ * gzvm_gfn_to_pfn_memslot() - Translate gfn (guest ipa) to pfn (host pa),
+ * result is in @pfn
+ * @memslot: Pointer to struct gzvm_memslot.
+ * @gfn: Guest frame number.
+ * @pfn: Host page frame number.
+ *
+ * Return:
+ * * 0 - Succeed
+ * * -EFAULT - Failed to convert
+ */
+int gzvm_gfn_to_pfn_memslot(struct gzvm_memslot *memslot, u64 gfn,
+ u64 *pfn)
+{
+ u64 __pfn;
+
+ if (!memslot)
+ return -EFAULT;
+
+ __pfn = __gzvm_gfn_to_pfn_memslot(memslot, gfn);
+ if (__pfn == GZVM_PA_ERR_BAD) {
+ *pfn = 0;
+ return -EFAULT;
+ }
+
+ *pfn = __pfn;
+
+ return 0;
+}
--
2.18.0
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