| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1207251170-5013-23-git-send-email-avi@qumranet.com>
Date: Thu, 3 Apr 2008 22:32:37 +0300
From: Avi Kivity <avi@...ranet.com>
To: kvm-devel@...ts.sourceforge.net
Cc: linux-kernel@...r.kernel.org, Marcelo Tosatti <mtosatti@...hat.com>
Subject: [PATCH 22/35] x86: KVM guest: hypercall based pte updates and TLB flushes
From: Marcelo Tosatti <mtosatti@...hat.com>
Hypercall based pte updates are faster than faults, and also allow use
of the lazy MMU mode to batch operations.
Don't report the feature if two dimensional paging is enabled.
[avi:
- guest/host split
- fix 32-bit truncation issues
- adjust to mmu_op]
Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Avi Kivity <avi@...ranet.com>
---
arch/x86/kernel/kvm.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 137 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index a8e36da..1bb6e97 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -25,6 +25,7 @@
#include <linux/kvm_para.h>
#include <linux/cpu.h>
#include <linux/mm.h>
+#include <linux/highmem.h>
/*
* No need for any "IO delay" on KVM
@@ -33,6 +34,122 @@ static void kvm_io_delay(void)
{
}
+static void kvm_mmu_op(void *buffer, unsigned len)
+{
+ int r;
+ unsigned long a1, a2;
+
+ do {
+ a1 = __pa(buffer);
+ a2 = 0; /* on i386 __pa() always returns <4G */
+ r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
+ buffer += r;
+ len -= r;
+ } while (len);
+}
+
+static void kvm_mmu_write(void *dest, u64 val)
+{
+ __u64 pte_phys;
+ struct kvm_mmu_op_write_pte wpte;
+
+#ifdef CONFIG_HIGHPTE
+ struct page *page;
+ unsigned long dst = (unsigned long) dest;
+
+ page = kmap_atomic_to_page(dest);
+ pte_phys = page_to_pfn(page);
+ pte_phys <<= PAGE_SHIFT;
+ pte_phys += (dst & ~(PAGE_MASK));
+#else
+ pte_phys = (unsigned long)__pa(dest);
+#endif
+ wpte.header.op = KVM_MMU_OP_WRITE_PTE;
+ wpte.pte_val = val;
+ wpte.pte_phys = pte_phys;
+
+ kvm_mmu_op(&wpte, sizeof wpte);
+}
+
+/*
+ * We only need to hook operations that are MMU writes. We hook these so that
+ * we can use lazy MMU mode to batch these operations. We could probably
+ * improve the performance of the host code if we used some of the information
+ * here to simplify processing of batched writes.
+ */
+static void kvm_set_pte(pte_t *ptep, pte_t pte)
+{
+ kvm_mmu_write(ptep, pte_val(pte));
+}
+
+static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ kvm_mmu_write(ptep, pte_val(pte));
+}
+
+static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
+{
+ kvm_mmu_write(pmdp, pmd_val(pmd));
+}
+
+#if PAGETABLE_LEVELS >= 3
+#ifdef CONFIG_X86_PAE
+static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+ kvm_mmu_write(ptep, pte_val(pte));
+}
+
+static void kvm_set_pte_present(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ kvm_mmu_write(ptep, pte_val(pte));
+}
+
+static void kvm_pte_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ kvm_mmu_write(ptep, 0);
+}
+
+static void kvm_pmd_clear(pmd_t *pmdp)
+{
+ kvm_mmu_write(pmdp, 0);
+}
+#endif
+
+static void kvm_set_pud(pud_t *pudp, pud_t pud)
+{
+ kvm_mmu_write(pudp, pud_val(pud));
+}
+
+#if PAGETABLE_LEVELS == 4
+static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
+{
+ kvm_mmu_write(pgdp, pgd_val(pgd));
+}
+#endif
+#endif /* PAGETABLE_LEVELS >= 3 */
+
+static void kvm_flush_tlb(void)
+{
+ struct kvm_mmu_op_flush_tlb ftlb = {
+ .header.op = KVM_MMU_OP_FLUSH_TLB,
+ };
+
+ kvm_mmu_op(&ftlb, sizeof ftlb);
+}
+
+static void kvm_release_pt(u32 pfn)
+{
+ struct kvm_mmu_op_release_pt rpt = {
+ .header.op = KVM_MMU_OP_RELEASE_PT,
+ .pt_phys = (u64)pfn << PAGE_SHIFT,
+ };
+
+ kvm_mmu_op(&rpt, sizeof rpt);
+}
+
static void paravirt_ops_setup(void)
{
pv_info.name = "KVM";
@@ -41,6 +158,26 @@ static void paravirt_ops_setup(void)
if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
pv_cpu_ops.io_delay = kvm_io_delay;
+ if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
+ pv_mmu_ops.set_pte = kvm_set_pte;
+ pv_mmu_ops.set_pte_at = kvm_set_pte_at;
+ pv_mmu_ops.set_pmd = kvm_set_pmd;
+#if PAGETABLE_LEVELS >= 3
+#ifdef CONFIG_X86_PAE
+ pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
+ pv_mmu_ops.set_pte_present = kvm_set_pte_present;
+ pv_mmu_ops.pte_clear = kvm_pte_clear;
+ pv_mmu_ops.pmd_clear = kvm_pmd_clear;
+#endif
+ pv_mmu_ops.set_pud = kvm_set_pud;
+#if PAGETABLE_LEVELS == 4
+ pv_mmu_ops.set_pgd = kvm_set_pgd;
+#endif
+#endif
+ pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
+ pv_mmu_ops.release_pt = kvm_release_pt;
+ pv_mmu_ops.release_pd = kvm_release_pt;
+ }
}
void __init kvm_guest_init(void)
--
1.5.4.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists