xen/riscv: implement sbi_remote_hfence_gvma()

Instruct the remote harts to execute one or more HFENCE.GVMA instructions,
covering the range of guest physical addresses between start_addr and
start_addr + size for all VMIDs.

The remote fence operation applies to the entire address space if either:
 - start_addr and size are both 0, or
 - size is equal to 2^XLEN-1.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/arch/riscv/include/asm/sbi.h

@@ -89,6 +89,25 @@ bool sbi_has_rfence(void);
 int sbi_remote_sfence_vma(const cpumask_t *cpu_mask, vaddr_t start,
                           size_t size);
 
+/*
+ * Instruct the remote harts to execute one or more HFENCE.GVMA
+ * instructions, covering the range of guest physical addresses
+ * in [start_addr, start_addr + size) for all VMIDs.
+ *
+ * Returns 0 if IPI was sent to all the targeted harts successfully
+ * or negative value if start_addr or size is not valid.
+ *
+ * The remote fence operation applies to the entire address space if either:
+ *  - start_addr and size are both 0, or
+ *  - size is equal to 2^XLEN-1.
+ *
+ * @cpu_mask a cpu mask containing all the target CPUs (in Xen space).
+ * @param start virtual address start
+ * @param size virtual address range size
+ */
+int sbi_remote_hfence_gvma(const cpumask_t *cpu_mask, vaddr_t start,
+                           size_t size);
+
 /*
  * Initialize SBI library
  *

xen/arch/riscv/sbi.c

@@ -258,6 +258,13 @@ int sbi_remote_sfence_vma(const cpumask_t *cpu_mask, vaddr_t start,
                       cpu_mask, start, size, 0, 0);
 }
 
+int sbi_remote_hfence_gvma(const cpumask_t *cpu_mask, vaddr_t start,
+                           size_t size)
+{
+    return sbi_rfence(SBI_EXT_RFENCE_REMOTE_HFENCE_GVMA,
+                      cpu_mask, start, size, 0, 0);
+}
+
 /* This function must always succeed. */
 #define sbi_get_spec_version()  \
     sbi_ext_base_func(SBI_EXT_BASE_GET_SPEC_VERSION)